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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SLUB: A slab allocator that limits cache line use instead of queuing
4 * objects in per cpu and per node lists.
5 *
6 * The allocator synchronizes using per slab locks or atomic operatios
7 * and only uses a centralized lock to manage a pool of partial slabs.
8 *
9 * (C) 2007 SGI, Christoph Lameter
10 * (C) 2011 Linux Foundation, Christoph Lameter
11 */
12
13#include <linux/mm.h>
14#include <linux/swap.h> /* struct reclaim_state */
15#include <linux/module.h>
16#include <linux/bit_spinlock.h>
17#include <linux/interrupt.h>
18#include <linux/bitops.h>
19#include <linux/slab.h>
20#include "slab.h"
21#include <linux/proc_fs.h>
22#include <linux/notifier.h>
23#include <linux/seq_file.h>
24#include <linux/kasan.h>
25#include <linux/cpu.h>
26#include <linux/cpuset.h>
27#include <linux/mempolicy.h>
28#include <linux/ctype.h>
29#include <linux/debugobjects.h>
30#include <linux/kallsyms.h>
31#include <linux/memory.h>
32#include <linux/math64.h>
33#include <linux/fault-inject.h>
34#include <linux/stacktrace.h>
35#include <linux/prefetch.h>
36#include <linux/memcontrol.h>
37#include <linux/random.h>
38
39#include <trace/events/kmem.h>
40
41#include "internal.h"
42
43/*
44 * Lock order:
45 * 1. slab_mutex (Global Mutex)
46 * 2. node->list_lock
47 * 3. slab_lock(page) (Only on some arches and for debugging)
48 *
49 * slab_mutex
50 *
51 * The role of the slab_mutex is to protect the list of all the slabs
52 * and to synchronize major metadata changes to slab cache structures.
53 *
54 * The slab_lock is only used for debugging and on arches that do not
55 * have the ability to do a cmpxchg_double. It only protects the second
56 * double word in the page struct. Meaning
57 * A. page->freelist -> List of object free in a page
58 * B. page->counters -> Counters of objects
59 * C. page->frozen -> frozen state
60 *
61 * If a slab is frozen then it is exempt from list management. It is not
62 * on any list. The processor that froze the slab is the one who can
63 * perform list operations on the page. Other processors may put objects
64 * onto the freelist but the processor that froze the slab is the only
65 * one that can retrieve the objects from the page's freelist.
66 *
67 * The list_lock protects the partial and full list on each node and
68 * the partial slab counter. If taken then no new slabs may be added or
69 * removed from the lists nor make the number of partial slabs be modified.
70 * (Note that the total number of slabs is an atomic value that may be
71 * modified without taking the list lock).
72 *
73 * The list_lock is a centralized lock and thus we avoid taking it as
74 * much as possible. As long as SLUB does not have to handle partial
75 * slabs, operations can continue without any centralized lock. F.e.
76 * allocating a long series of objects that fill up slabs does not require
77 * the list lock.
78 * Interrupts are disabled during allocation and deallocation in order to
79 * make the slab allocator safe to use in the context of an irq. In addition
80 * interrupts are disabled to ensure that the processor does not change
81 * while handling per_cpu slabs, due to kernel preemption.
82 *
83 * SLUB assigns one slab for allocation to each processor.
84 * Allocations only occur from these slabs called cpu slabs.
85 *
86 * Slabs with free elements are kept on a partial list and during regular
87 * operations no list for full slabs is used. If an object in a full slab is
88 * freed then the slab will show up again on the partial lists.
89 * We track full slabs for debugging purposes though because otherwise we
90 * cannot scan all objects.
91 *
92 * Slabs are freed when they become empty. Teardown and setup is
93 * minimal so we rely on the page allocators per cpu caches for
94 * fast frees and allocs.
95 *
96 * Overloading of page flags that are otherwise used for LRU management.
97 *
98 * PageActive The slab is frozen and exempt from list processing.
99 * This means that the slab is dedicated to a purpose
100 * such as satisfying allocations for a specific
101 * processor. Objects may be freed in the slab while
102 * it is frozen but slab_free will then skip the usual
103 * list operations. It is up to the processor holding
104 * the slab to integrate the slab into the slab lists
105 * when the slab is no longer needed.
106 *
107 * One use of this flag is to mark slabs that are
108 * used for allocations. Then such a slab becomes a cpu
109 * slab. The cpu slab may be equipped with an additional
110 * freelist that allows lockless access to
111 * free objects in addition to the regular freelist
112 * that requires the slab lock.
113 *
114 * PageError Slab requires special handling due to debug
115 * options set. This moves slab handling out of
116 * the fast path and disables lockless freelists.
117 */
118
119static inline int kmem_cache_debug(struct kmem_cache *s)
120{
121#ifdef CONFIG_SLUB_DEBUG
122 return unlikely(s->flags & SLAB_DEBUG_FLAGS);
123#else
124 return 0;
125#endif
126}
127
128void *fixup_red_left(struct kmem_cache *s, void *p)
129{
130 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE)
131 p += s->red_left_pad;
132
133 return p;
134}
135
136static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
137{
138#ifdef CONFIG_SLUB_CPU_PARTIAL
139 return !kmem_cache_debug(s);
140#else
141 return false;
142#endif
143}
144
145/*
146 * Issues still to be resolved:
147 *
148 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
149 *
150 * - Variable sizing of the per node arrays
151 */
152
153/* Enable to test recovery from slab corruption on boot */
154#undef SLUB_RESILIENCY_TEST
155
156/* Enable to log cmpxchg failures */
157#undef SLUB_DEBUG_CMPXCHG
158
159/*
160 * Mininum number of partial slabs. These will be left on the partial
161 * lists even if they are empty. kmem_cache_shrink may reclaim them.
162 */
163#define MIN_PARTIAL 5
164
165/*
166 * Maximum number of desirable partial slabs.
167 * The existence of more partial slabs makes kmem_cache_shrink
168 * sort the partial list by the number of objects in use.
169 */
170#define MAX_PARTIAL 10
171
172#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
173 SLAB_POISON | SLAB_STORE_USER)
174
175/*
176 * These debug flags cannot use CMPXCHG because there might be consistency
177 * issues when checking or reading debug information
178 */
179#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
180 SLAB_TRACE)
181
182
183/*
184 * Debugging flags that require metadata to be stored in the slab. These get
185 * disabled when slub_debug=O is used and a cache's min order increases with
186 * metadata.
187 */
188#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
189
190#define OO_SHIFT 16
191#define OO_MASK ((1 << OO_SHIFT) - 1)
192#define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */
193
194/* Internal SLUB flags */
195/* Poison object */
196#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
197/* Use cmpxchg_double */
198#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
199
200/*
201 * Tracking user of a slab.
202 */
203#define TRACK_ADDRS_COUNT 16
204struct track {
205 unsigned long addr; /* Called from address */
206#ifdef CONFIG_STACKTRACE
207 unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
208#endif
209 int cpu; /* Was running on cpu */
210 int pid; /* Pid context */
211 unsigned long when; /* When did the operation occur */
212};
213
214enum track_item { TRACK_ALLOC, TRACK_FREE };
215
216#ifdef CONFIG_SYSFS
217static int sysfs_slab_add(struct kmem_cache *);
218static int sysfs_slab_alias(struct kmem_cache *, const char *);
219static void memcg_propagate_slab_attrs(struct kmem_cache *s);
220static void sysfs_slab_remove(struct kmem_cache *s);
221#else
222static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
223static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
224 { return 0; }
225static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { }
226static inline void sysfs_slab_remove(struct kmem_cache *s) { }
227#endif
228
229static inline void stat(const struct kmem_cache *s, enum stat_item si)
230{
231#ifdef CONFIG_SLUB_STATS
232 /*
233 * The rmw is racy on a preemptible kernel but this is acceptable, so
234 * avoid this_cpu_add()'s irq-disable overhead.
235 */
236 raw_cpu_inc(s->cpu_slab->stat[si]);
237#endif
238}
239
240/********************************************************************
241 * Core slab cache functions
242 *******************************************************************/
243
244/*
245 * Returns freelist pointer (ptr). With hardening, this is obfuscated
246 * with an XOR of the address where the pointer is held and a per-cache
247 * random number.
248 */
249static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
250 unsigned long ptr_addr)
251{
252#ifdef CONFIG_SLAB_FREELIST_HARDENED
253 return (void *)((unsigned long)ptr ^ s->random ^ ptr_addr);
254#else
255 return ptr;
256#endif
257}
258
259/* Returns the freelist pointer recorded at location ptr_addr. */
260static inline void *freelist_dereference(const struct kmem_cache *s,
261 void *ptr_addr)
262{
263 return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
264 (unsigned long)ptr_addr);
265}
266
267static inline void *get_freepointer(struct kmem_cache *s, void *object)
268{
269 return freelist_dereference(s, object + s->offset);
270}
271
272static void prefetch_freepointer(const struct kmem_cache *s, void *object)
273{
274 if (object)
275 prefetch(freelist_dereference(s, object + s->offset));
276}
277
278static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
279{
280 unsigned long freepointer_addr;
281 void *p;
282
283 if (!debug_pagealloc_enabled())
284 return get_freepointer(s, object);
285
286 freepointer_addr = (unsigned long)object + s->offset;
287 probe_kernel_read(&p, (void **)freepointer_addr, sizeof(p));
288 return freelist_ptr(s, p, freepointer_addr);
289}
290
291static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
292{
293 unsigned long freeptr_addr = (unsigned long)object + s->offset;
294
295#ifdef CONFIG_SLAB_FREELIST_HARDENED
296 BUG_ON(object == fp); /* naive detection of double free or corruption */
297#endif
298
299 *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
300}
301
302/* Loop over all objects in a slab */
303#define for_each_object(__p, __s, __addr, __objects) \
304 for (__p = fixup_red_left(__s, __addr); \
305 __p < (__addr) + (__objects) * (__s)->size; \
306 __p += (__s)->size)
307
308#define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
309 for (__p = fixup_red_left(__s, __addr), __idx = 1; \
310 __idx <= __objects; \
311 __p += (__s)->size, __idx++)
312
313/* Determine object index from a given position */
314static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr)
315{
316 return (p - addr) / s->size;
317}
318
319static inline unsigned int order_objects(unsigned int order, unsigned int size, unsigned int reserved)
320{
321 return (((unsigned int)PAGE_SIZE << order) - reserved) / size;
322}
323
324static inline struct kmem_cache_order_objects oo_make(unsigned int order,
325 unsigned int size, unsigned int reserved)
326{
327 struct kmem_cache_order_objects x = {
328 (order << OO_SHIFT) + order_objects(order, size, reserved)
329 };
330
331 return x;
332}
333
334static inline unsigned int oo_order(struct kmem_cache_order_objects x)
335{
336 return x.x >> OO_SHIFT;
337}
338
339static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
340{
341 return x.x & OO_MASK;
342}
343
344/*
345 * Per slab locking using the pagelock
346 */
347static __always_inline void slab_lock(struct page *page)
348{
349 VM_BUG_ON_PAGE(PageTail(page), page);
350 bit_spin_lock(PG_locked, &page->flags);
351}
352
353static __always_inline void slab_unlock(struct page *page)
354{
355 VM_BUG_ON_PAGE(PageTail(page), page);
356 __bit_spin_unlock(PG_locked, &page->flags);
357}
358
359static inline void set_page_slub_counters(struct page *page, unsigned long counters_new)
360{
361 struct page tmp;
362 tmp.counters = counters_new;
363 /*
364 * page->counters can cover frozen/inuse/objects as well
365 * as page->_refcount. If we assign to ->counters directly
366 * we run the risk of losing updates to page->_refcount, so
367 * be careful and only assign to the fields we need.
368 */
369 page->frozen = tmp.frozen;
370 page->inuse = tmp.inuse;
371 page->objects = tmp.objects;
372}
373
374/* Interrupts must be disabled (for the fallback code to work right) */
375static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
376 void *freelist_old, unsigned long counters_old,
377 void *freelist_new, unsigned long counters_new,
378 const char *n)
379{
380 VM_BUG_ON(!irqs_disabled());
381#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
382 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
383 if (s->flags & __CMPXCHG_DOUBLE) {
384 if (cmpxchg_double(&page->freelist, &page->counters,
385 freelist_old, counters_old,
386 freelist_new, counters_new))
387 return true;
388 } else
389#endif
390 {
391 slab_lock(page);
392 if (page->freelist == freelist_old &&
393 page->counters == counters_old) {
394 page->freelist = freelist_new;
395 set_page_slub_counters(page, counters_new);
396 slab_unlock(page);
397 return true;
398 }
399 slab_unlock(page);
400 }
401
402 cpu_relax();
403 stat(s, CMPXCHG_DOUBLE_FAIL);
404
405#ifdef SLUB_DEBUG_CMPXCHG
406 pr_info("%s %s: cmpxchg double redo ", n, s->name);
407#endif
408
409 return false;
410}
411
412static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
413 void *freelist_old, unsigned long counters_old,
414 void *freelist_new, unsigned long counters_new,
415 const char *n)
416{
417#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
418 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
419 if (s->flags & __CMPXCHG_DOUBLE) {
420 if (cmpxchg_double(&page->freelist, &page->counters,
421 freelist_old, counters_old,
422 freelist_new, counters_new))
423 return true;
424 } else
425#endif
426 {
427 unsigned long flags;
428
429 local_irq_save(flags);
430 slab_lock(page);
431 if (page->freelist == freelist_old &&
432 page->counters == counters_old) {
433 page->freelist = freelist_new;
434 set_page_slub_counters(page, counters_new);
435 slab_unlock(page);
436 local_irq_restore(flags);
437 return true;
438 }
439 slab_unlock(page);
440 local_irq_restore(flags);
441 }
442
443 cpu_relax();
444 stat(s, CMPXCHG_DOUBLE_FAIL);
445
446#ifdef SLUB_DEBUG_CMPXCHG
447 pr_info("%s %s: cmpxchg double redo ", n, s->name);
448#endif
449
450 return false;
451}
452
453#ifdef CONFIG_SLUB_DEBUG
454/*
455 * Determine a map of object in use on a page.
456 *
457 * Node listlock must be held to guarantee that the page does
458 * not vanish from under us.
459 */
460static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
461{
462 void *p;
463 void *addr = page_address(page);
464
465 for (p = page->freelist; p; p = get_freepointer(s, p))
466 set_bit(slab_index(p, s, addr), map);
467}
468
469static inline unsigned int size_from_object(struct kmem_cache *s)
470{
471 if (s->flags & SLAB_RED_ZONE)
472 return s->size - s->red_left_pad;
473
474 return s->size;
475}
476
477static inline void *restore_red_left(struct kmem_cache *s, void *p)
478{
479 if (s->flags & SLAB_RED_ZONE)
480 p -= s->red_left_pad;
481
482 return p;
483}
484
485/*
486 * Debug settings:
487 */
488#if defined(CONFIG_SLUB_DEBUG_ON)
489static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
490#else
491static slab_flags_t slub_debug;
492#endif
493
494static char *slub_debug_slabs;
495static int disable_higher_order_debug;
496
497/*
498 * slub is about to manipulate internal object metadata. This memory lies
499 * outside the range of the allocated object, so accessing it would normally
500 * be reported by kasan as a bounds error. metadata_access_enable() is used
501 * to tell kasan that these accesses are OK.
502 */
503static inline void metadata_access_enable(void)
504{
505 kasan_disable_current();
506}
507
508static inline void metadata_access_disable(void)
509{
510 kasan_enable_current();
511}
512
513/*
514 * Object debugging
515 */
516
517/* Verify that a pointer has an address that is valid within a slab page */
518static inline int check_valid_pointer(struct kmem_cache *s,
519 struct page *page, void *object)
520{
521 void *base;
522
523 if (!object)
524 return 1;
525
526 base = page_address(page);
527 object = restore_red_left(s, object);
528 if (object < base || object >= base + page->objects * s->size ||
529 (object - base) % s->size) {
530 return 0;
531 }
532
533 return 1;
534}
535
536static void print_section(char *level, char *text, u8 *addr,
537 unsigned int length)
538{
539 metadata_access_enable();
540 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
541 length, 1);
542 metadata_access_disable();
543}
544
545static struct track *get_track(struct kmem_cache *s, void *object,
546 enum track_item alloc)
547{
548 struct track *p;
549
550 if (s->offset)
551 p = object + s->offset + sizeof(void *);
552 else
553 p = object + s->inuse;
554
555 return p + alloc;
556}
557
558static void set_track(struct kmem_cache *s, void *object,
559 enum track_item alloc, unsigned long addr)
560{
561 struct track *p = get_track(s, object, alloc);
562
563 if (addr) {
564#ifdef CONFIG_STACKTRACE
565 struct stack_trace trace;
566 int i;
567
568 trace.nr_entries = 0;
569 trace.max_entries = TRACK_ADDRS_COUNT;
570 trace.entries = p->addrs;
571 trace.skip = 3;
572 metadata_access_enable();
573 save_stack_trace(&trace);
574 metadata_access_disable();
575
576 /* See rant in lockdep.c */
577 if (trace.nr_entries != 0 &&
578 trace.entries[trace.nr_entries - 1] == ULONG_MAX)
579 trace.nr_entries--;
580
581 for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
582 p->addrs[i] = 0;
583#endif
584 p->addr = addr;
585 p->cpu = smp_processor_id();
586 p->pid = current->pid;
587 p->when = jiffies;
588 } else
589 memset(p, 0, sizeof(struct track));
590}
591
592static void init_tracking(struct kmem_cache *s, void *object)
593{
594 if (!(s->flags & SLAB_STORE_USER))
595 return;
596
597 set_track(s, object, TRACK_FREE, 0UL);
598 set_track(s, object, TRACK_ALLOC, 0UL);
599}
600
601static void print_track(const char *s, struct track *t, unsigned long pr_time)
602{
603 if (!t->addr)
604 return;
605
606 pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
607 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
608#ifdef CONFIG_STACKTRACE
609 {
610 int i;
611 for (i = 0; i < TRACK_ADDRS_COUNT; i++)
612 if (t->addrs[i])
613 pr_err("\t%pS\n", (void *)t->addrs[i]);
614 else
615 break;
616 }
617#endif
618}
619
620static void print_tracking(struct kmem_cache *s, void *object)
621{
622 unsigned long pr_time = jiffies;
623 if (!(s->flags & SLAB_STORE_USER))
624 return;
625
626 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
627 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
628}
629
630static void print_page_info(struct page *page)
631{
632 pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
633 page, page->objects, page->inuse, page->freelist, page->flags);
634
635}
636
637static void slab_bug(struct kmem_cache *s, char *fmt, ...)
638{
639 struct va_format vaf;
640 va_list args;
641
642 va_start(args, fmt);
643 vaf.fmt = fmt;
644 vaf.va = &args;
645 pr_err("=============================================================================\n");
646 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
647 pr_err("-----------------------------------------------------------------------------\n\n");
648
649 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
650 va_end(args);
651}
652
653static void slab_fix(struct kmem_cache *s, char *fmt, ...)
654{
655 struct va_format vaf;
656 va_list args;
657
658 va_start(args, fmt);
659 vaf.fmt = fmt;
660 vaf.va = &args;
661 pr_err("FIX %s: %pV\n", s->name, &vaf);
662 va_end(args);
663}
664
665static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
666{
667 unsigned int off; /* Offset of last byte */
668 u8 *addr = page_address(page);
669
670 print_tracking(s, p);
671
672 print_page_info(page);
673
674 pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
675 p, p - addr, get_freepointer(s, p));
676
677 if (s->flags & SLAB_RED_ZONE)
678 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
679 s->red_left_pad);
680 else if (p > addr + 16)
681 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
682
683 print_section(KERN_ERR, "Object ", p,
684 min_t(unsigned int, s->object_size, PAGE_SIZE));
685 if (s->flags & SLAB_RED_ZONE)
686 print_section(KERN_ERR, "Redzone ", p + s->object_size,
687 s->inuse - s->object_size);
688
689 if (s->offset)
690 off = s->offset + sizeof(void *);
691 else
692 off = s->inuse;
693
694 if (s->flags & SLAB_STORE_USER)
695 off += 2 * sizeof(struct track);
696
697 off += kasan_metadata_size(s);
698
699 if (off != size_from_object(s))
700 /* Beginning of the filler is the free pointer */
701 print_section(KERN_ERR, "Padding ", p + off,
702 size_from_object(s) - off);
703
704 dump_stack();
705}
706
707void object_err(struct kmem_cache *s, struct page *page,
708 u8 *object, char *reason)
709{
710 slab_bug(s, "%s", reason);
711 print_trailer(s, page, object);
712}
713
714static void slab_err(struct kmem_cache *s, struct page *page,
715 const char *fmt, ...)
716{
717 va_list args;
718 char buf[100];
719
720 va_start(args, fmt);
721 vsnprintf(buf, sizeof(buf), fmt, args);
722 va_end(args);
723 slab_bug(s, "%s", buf);
724 print_page_info(page);
725 dump_stack();
726}
727
728static void init_object(struct kmem_cache *s, void *object, u8 val)
729{
730 u8 *p = object;
731
732 if (s->flags & SLAB_RED_ZONE)
733 memset(p - s->red_left_pad, val, s->red_left_pad);
734
735 if (s->flags & __OBJECT_POISON) {
736 memset(p, POISON_FREE, s->object_size - 1);
737 p[s->object_size - 1] = POISON_END;
738 }
739
740 if (s->flags & SLAB_RED_ZONE)
741 memset(p + s->object_size, val, s->inuse - s->object_size);
742}
743
744static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
745 void *from, void *to)
746{
747 slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
748 memset(from, data, to - from);
749}
750
751static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
752 u8 *object, char *what,
753 u8 *start, unsigned int value, unsigned int bytes)
754{
755 u8 *fault;
756 u8 *end;
757
758 metadata_access_enable();
759 fault = memchr_inv(start, value, bytes);
760 metadata_access_disable();
761 if (!fault)
762 return 1;
763
764 end = start + bytes;
765 while (end > fault && end[-1] == value)
766 end--;
767
768 slab_bug(s, "%s overwritten", what);
769 pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
770 fault, end - 1, fault[0], value);
771 print_trailer(s, page, object);
772
773 restore_bytes(s, what, value, fault, end);
774 return 0;
775}
776
777/*
778 * Object layout:
779 *
780 * object address
781 * Bytes of the object to be managed.
782 * If the freepointer may overlay the object then the free
783 * pointer is the first word of the object.
784 *
785 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
786 * 0xa5 (POISON_END)
787 *
788 * object + s->object_size
789 * Padding to reach word boundary. This is also used for Redzoning.
790 * Padding is extended by another word if Redzoning is enabled and
791 * object_size == inuse.
792 *
793 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
794 * 0xcc (RED_ACTIVE) for objects in use.
795 *
796 * object + s->inuse
797 * Meta data starts here.
798 *
799 * A. Free pointer (if we cannot overwrite object on free)
800 * B. Tracking data for SLAB_STORE_USER
801 * C. Padding to reach required alignment boundary or at mininum
802 * one word if debugging is on to be able to detect writes
803 * before the word boundary.
804 *
805 * Padding is done using 0x5a (POISON_INUSE)
806 *
807 * object + s->size
808 * Nothing is used beyond s->size.
809 *
810 * If slabcaches are merged then the object_size and inuse boundaries are mostly
811 * ignored. And therefore no slab options that rely on these boundaries
812 * may be used with merged slabcaches.
813 */
814
815static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
816{
817 unsigned long off = s->inuse; /* The end of info */
818
819 if (s->offset)
820 /* Freepointer is placed after the object. */
821 off += sizeof(void *);
822
823 if (s->flags & SLAB_STORE_USER)
824 /* We also have user information there */
825 off += 2 * sizeof(struct track);
826
827 off += kasan_metadata_size(s);
828
829 if (size_from_object(s) == off)
830 return 1;
831
832 return check_bytes_and_report(s, page, p, "Object padding",
833 p + off, POISON_INUSE, size_from_object(s) - off);
834}
835
836/* Check the pad bytes at the end of a slab page */
837static int slab_pad_check(struct kmem_cache *s, struct page *page)
838{
839 u8 *start;
840 u8 *fault;
841 u8 *end;
842 u8 *pad;
843 int length;
844 int remainder;
845
846 if (!(s->flags & SLAB_POISON))
847 return 1;
848
849 start = page_address(page);
850 length = (PAGE_SIZE << compound_order(page)) - s->reserved;
851 end = start + length;
852 remainder = length % s->size;
853 if (!remainder)
854 return 1;
855
856 pad = end - remainder;
857 metadata_access_enable();
858 fault = memchr_inv(pad, POISON_INUSE, remainder);
859 metadata_access_disable();
860 if (!fault)
861 return 1;
862 while (end > fault && end[-1] == POISON_INUSE)
863 end--;
864
865 slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
866 print_section(KERN_ERR, "Padding ", pad, remainder);
867
868 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
869 return 0;
870}
871
872static int check_object(struct kmem_cache *s, struct page *page,
873 void *object, u8 val)
874{
875 u8 *p = object;
876 u8 *endobject = object + s->object_size;
877
878 if (s->flags & SLAB_RED_ZONE) {
879 if (!check_bytes_and_report(s, page, object, "Redzone",
880 object - s->red_left_pad, val, s->red_left_pad))
881 return 0;
882
883 if (!check_bytes_and_report(s, page, object, "Redzone",
884 endobject, val, s->inuse - s->object_size))
885 return 0;
886 } else {
887 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
888 check_bytes_and_report(s, page, p, "Alignment padding",
889 endobject, POISON_INUSE,
890 s->inuse - s->object_size);
891 }
892 }
893
894 if (s->flags & SLAB_POISON) {
895 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
896 (!check_bytes_and_report(s, page, p, "Poison", p,
897 POISON_FREE, s->object_size - 1) ||
898 !check_bytes_and_report(s, page, p, "Poison",
899 p + s->object_size - 1, POISON_END, 1)))
900 return 0;
901 /*
902 * check_pad_bytes cleans up on its own.
903 */
904 check_pad_bytes(s, page, p);
905 }
906
907 if (!s->offset && val == SLUB_RED_ACTIVE)
908 /*
909 * Object and freepointer overlap. Cannot check
910 * freepointer while object is allocated.
911 */
912 return 1;
913
914 /* Check free pointer validity */
915 if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
916 object_err(s, page, p, "Freepointer corrupt");
917 /*
918 * No choice but to zap it and thus lose the remainder
919 * of the free objects in this slab. May cause
920 * another error because the object count is now wrong.
921 */
922 set_freepointer(s, p, NULL);
923 return 0;
924 }
925 return 1;
926}
927
928static int check_slab(struct kmem_cache *s, struct page *page)
929{
930 int maxobj;
931
932 VM_BUG_ON(!irqs_disabled());
933
934 if (!PageSlab(page)) {
935 slab_err(s, page, "Not a valid slab page");
936 return 0;
937 }
938
939 maxobj = order_objects(compound_order(page), s->size, s->reserved);
940 if (page->objects > maxobj) {
941 slab_err(s, page, "objects %u > max %u",
942 page->objects, maxobj);
943 return 0;
944 }
945 if (page->inuse > page->objects) {
946 slab_err(s, page, "inuse %u > max %u",
947 page->inuse, page->objects);
948 return 0;
949 }
950 /* Slab_pad_check fixes things up after itself */
951 slab_pad_check(s, page);
952 return 1;
953}
954
955/*
956 * Determine if a certain object on a page is on the freelist. Must hold the
957 * slab lock to guarantee that the chains are in a consistent state.
958 */
959static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
960{
961 int nr = 0;
962 void *fp;
963 void *object = NULL;
964 int max_objects;
965
966 fp = page->freelist;
967 while (fp && nr <= page->objects) {
968 if (fp == search)
969 return 1;
970 if (!check_valid_pointer(s, page, fp)) {
971 if (object) {
972 object_err(s, page, object,
973 "Freechain corrupt");
974 set_freepointer(s, object, NULL);
975 } else {
976 slab_err(s, page, "Freepointer corrupt");
977 page->freelist = NULL;
978 page->inuse = page->objects;
979 slab_fix(s, "Freelist cleared");
980 return 0;
981 }
982 break;
983 }
984 object = fp;
985 fp = get_freepointer(s, object);
986 nr++;
987 }
988
989 max_objects = order_objects(compound_order(page), s->size, s->reserved);
990 if (max_objects > MAX_OBJS_PER_PAGE)
991 max_objects = MAX_OBJS_PER_PAGE;
992
993 if (page->objects != max_objects) {
994 slab_err(s, page, "Wrong number of objects. Found %d but should be %d",
995 page->objects, max_objects);
996 page->objects = max_objects;
997 slab_fix(s, "Number of objects adjusted.");
998 }
999 if (page->inuse != page->objects - nr) {
1000 slab_err(s, page, "Wrong object count. Counter is %d but counted were %d",
1001 page->inuse, page->objects - nr);
1002 page->inuse = page->objects - nr;
1003 slab_fix(s, "Object count adjusted.");
1004 }
1005 return search == NULL;
1006}
1007
1008static void trace(struct kmem_cache *s, struct page *page, void *object,
1009 int alloc)
1010{
1011 if (s->flags & SLAB_TRACE) {
1012 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1013 s->name,
1014 alloc ? "alloc" : "free",
1015 object, page->inuse,
1016 page->freelist);
1017
1018 if (!alloc)
1019 print_section(KERN_INFO, "Object ", (void *)object,
1020 s->object_size);
1021
1022 dump_stack();
1023 }
1024}
1025
1026/*
1027 * Tracking of fully allocated slabs for debugging purposes.
1028 */
1029static void add_full(struct kmem_cache *s,
1030 struct kmem_cache_node *n, struct page *page)
1031{
1032 if (!(s->flags & SLAB_STORE_USER))
1033 return;
1034
1035 lockdep_assert_held(&n->list_lock);
1036 list_add(&page->lru, &n->full);
1037}
1038
1039static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page)
1040{
1041 if (!(s->flags & SLAB_STORE_USER))
1042 return;
1043
1044 lockdep_assert_held(&n->list_lock);
1045 list_del(&page->lru);
1046}
1047
1048/* Tracking of the number of slabs for debugging purposes */
1049static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1050{
1051 struct kmem_cache_node *n = get_node(s, node);
1052
1053 return atomic_long_read(&n->nr_slabs);
1054}
1055
1056static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1057{
1058 return atomic_long_read(&n->nr_slabs);
1059}
1060
1061static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1062{
1063 struct kmem_cache_node *n = get_node(s, node);
1064
1065 /*
1066 * May be called early in order to allocate a slab for the
1067 * kmem_cache_node structure. Solve the chicken-egg
1068 * dilemma by deferring the increment of the count during
1069 * bootstrap (see early_kmem_cache_node_alloc).
1070 */
1071 if (likely(n)) {
1072 atomic_long_inc(&n->nr_slabs);
1073 atomic_long_add(objects, &n->total_objects);
1074 }
1075}
1076static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1077{
1078 struct kmem_cache_node *n = get_node(s, node);
1079
1080 atomic_long_dec(&n->nr_slabs);
1081 atomic_long_sub(objects, &n->total_objects);
1082}
1083
1084/* Object debug checks for alloc/free paths */
1085static void setup_object_debug(struct kmem_cache *s, struct page *page,
1086 void *object)
1087{
1088 if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1089 return;
1090
1091 init_object(s, object, SLUB_RED_INACTIVE);
1092 init_tracking(s, object);
1093}
1094
1095static inline int alloc_consistency_checks(struct kmem_cache *s,
1096 struct page *page,
1097 void *object, unsigned long addr)
1098{
1099 if (!check_slab(s, page))
1100 return 0;
1101
1102 if (!check_valid_pointer(s, page, object)) {
1103 object_err(s, page, object, "Freelist Pointer check fails");
1104 return 0;
1105 }
1106
1107 if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1108 return 0;
1109
1110 return 1;
1111}
1112
1113static noinline int alloc_debug_processing(struct kmem_cache *s,
1114 struct page *page,
1115 void *object, unsigned long addr)
1116{
1117 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1118 if (!alloc_consistency_checks(s, page, object, addr))
1119 goto bad;
1120 }
1121
1122 /* Success perform special debug activities for allocs */
1123 if (s->flags & SLAB_STORE_USER)
1124 set_track(s, object, TRACK_ALLOC, addr);
1125 trace(s, page, object, 1);
1126 init_object(s, object, SLUB_RED_ACTIVE);
1127 return 1;
1128
1129bad:
1130 if (PageSlab(page)) {
1131 /*
1132 * If this is a slab page then lets do the best we can
1133 * to avoid issues in the future. Marking all objects
1134 * as used avoids touching the remaining objects.
1135 */
1136 slab_fix(s, "Marking all objects used");
1137 page->inuse = page->objects;
1138 page->freelist = NULL;
1139 }
1140 return 0;
1141}
1142
1143static inline int free_consistency_checks(struct kmem_cache *s,
1144 struct page *page, void *object, unsigned long addr)
1145{
1146 if (!check_valid_pointer(s, page, object)) {
1147 slab_err(s, page, "Invalid object pointer 0x%p", object);
1148 return 0;
1149 }
1150
1151 if (on_freelist(s, page, object)) {
1152 object_err(s, page, object, "Object already free");
1153 return 0;
1154 }
1155
1156 if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1157 return 0;
1158
1159 if (unlikely(s != page->slab_cache)) {
1160 if (!PageSlab(page)) {
1161 slab_err(s, page, "Attempt to free object(0x%p) outside of slab",
1162 object);
1163 } else if (!page->slab_cache) {
1164 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1165 object);
1166 dump_stack();
1167 } else
1168 object_err(s, page, object,
1169 "page slab pointer corrupt.");
1170 return 0;
1171 }
1172 return 1;
1173}
1174
1175/* Supports checking bulk free of a constructed freelist */
1176static noinline int free_debug_processing(
1177 struct kmem_cache *s, struct page *page,
1178 void *head, void *tail, int bulk_cnt,
1179 unsigned long addr)
1180{
1181 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1182 void *object = head;
1183 int cnt = 0;
1184 unsigned long uninitialized_var(flags);
1185 int ret = 0;
1186
1187 spin_lock_irqsave(&n->list_lock, flags);
1188 slab_lock(page);
1189
1190 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1191 if (!check_slab(s, page))
1192 goto out;
1193 }
1194
1195next_object:
1196 cnt++;
1197
1198 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1199 if (!free_consistency_checks(s, page, object, addr))
1200 goto out;
1201 }
1202
1203 if (s->flags & SLAB_STORE_USER)
1204 set_track(s, object, TRACK_FREE, addr);
1205 trace(s, page, object, 0);
1206 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
1207 init_object(s, object, SLUB_RED_INACTIVE);
1208
1209 /* Reached end of constructed freelist yet? */
1210 if (object != tail) {
1211 object = get_freepointer(s, object);
1212 goto next_object;
1213 }
1214 ret = 1;
1215
1216out:
1217 if (cnt != bulk_cnt)
1218 slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n",
1219 bulk_cnt, cnt);
1220
1221 slab_unlock(page);
1222 spin_unlock_irqrestore(&n->list_lock, flags);
1223 if (!ret)
1224 slab_fix(s, "Object at 0x%p not freed", object);
1225 return ret;
1226}
1227
1228static int __init setup_slub_debug(char *str)
1229{
1230 slub_debug = DEBUG_DEFAULT_FLAGS;
1231 if (*str++ != '=' || !*str)
1232 /*
1233 * No options specified. Switch on full debugging.
1234 */
1235 goto out;
1236
1237 if (*str == ',')
1238 /*
1239 * No options but restriction on slabs. This means full
1240 * debugging for slabs matching a pattern.
1241 */
1242 goto check_slabs;
1243
1244 slub_debug = 0;
1245 if (*str == '-')
1246 /*
1247 * Switch off all debugging measures.
1248 */
1249 goto out;
1250
1251 /*
1252 * Determine which debug features should be switched on
1253 */
1254 for (; *str && *str != ','; str++) {
1255 switch (tolower(*str)) {
1256 case 'f':
1257 slub_debug |= SLAB_CONSISTENCY_CHECKS;
1258 break;
1259 case 'z':
1260 slub_debug |= SLAB_RED_ZONE;
1261 break;
1262 case 'p':
1263 slub_debug |= SLAB_POISON;
1264 break;
1265 case 'u':
1266 slub_debug |= SLAB_STORE_USER;
1267 break;
1268 case 't':
1269 slub_debug |= SLAB_TRACE;
1270 break;
1271 case 'a':
1272 slub_debug |= SLAB_FAILSLAB;
1273 break;
1274 case 'o':
1275 /*
1276 * Avoid enabling debugging on caches if its minimum
1277 * order would increase as a result.
1278 */
1279 disable_higher_order_debug = 1;
1280 break;
1281 default:
1282 pr_err("slub_debug option '%c' unknown. skipped\n",
1283 *str);
1284 }
1285 }
1286
1287check_slabs:
1288 if (*str == ',')
1289 slub_debug_slabs = str + 1;
1290out:
1291 return 1;
1292}
1293
1294__setup("slub_debug", setup_slub_debug);
1295
1296slab_flags_t kmem_cache_flags(unsigned int object_size,
1297 slab_flags_t flags, const char *name,
1298 void (*ctor)(void *))
1299{
1300 /*
1301 * Enable debugging if selected on the kernel commandline.
1302 */
1303 if (slub_debug && (!slub_debug_slabs || (name &&
1304 !strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)))))
1305 flags |= slub_debug;
1306
1307 return flags;
1308}
1309#else /* !CONFIG_SLUB_DEBUG */
1310static inline void setup_object_debug(struct kmem_cache *s,
1311 struct page *page, void *object) {}
1312
1313static inline int alloc_debug_processing(struct kmem_cache *s,
1314 struct page *page, void *object, unsigned long addr) { return 0; }
1315
1316static inline int free_debug_processing(
1317 struct kmem_cache *s, struct page *page,
1318 void *head, void *tail, int bulk_cnt,
1319 unsigned long addr) { return 0; }
1320
1321static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1322 { return 1; }
1323static inline int check_object(struct kmem_cache *s, struct page *page,
1324 void *object, u8 val) { return 1; }
1325static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1326 struct page *page) {}
1327static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1328 struct page *page) {}
1329slab_flags_t kmem_cache_flags(unsigned int object_size,
1330 slab_flags_t flags, const char *name,
1331 void (*ctor)(void *))
1332{
1333 return flags;
1334}
1335#define slub_debug 0
1336
1337#define disable_higher_order_debug 0
1338
1339static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1340 { return 0; }
1341static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1342 { return 0; }
1343static inline void inc_slabs_node(struct kmem_cache *s, int node,
1344 int objects) {}
1345static inline void dec_slabs_node(struct kmem_cache *s, int node,
1346 int objects) {}
1347
1348#endif /* CONFIG_SLUB_DEBUG */
1349
1350/*
1351 * Hooks for other subsystems that check memory allocations. In a typical
1352 * production configuration these hooks all should produce no code at all.
1353 */
1354static inline void kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags)
1355{
1356 kmemleak_alloc(ptr, size, 1, flags);
1357 kasan_kmalloc_large(ptr, size, flags);
1358}
1359
1360static __always_inline void kfree_hook(void *x)
1361{
1362 kmemleak_free(x);
1363 kasan_kfree_large(x, _RET_IP_);
1364}
1365
1366static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x)
1367{
1368 kmemleak_free_recursive(x, s->flags);
1369
1370 /*
1371 * Trouble is that we may no longer disable interrupts in the fast path
1372 * So in order to make the debug calls that expect irqs to be
1373 * disabled we need to disable interrupts temporarily.
1374 */
1375#ifdef CONFIG_LOCKDEP
1376 {
1377 unsigned long flags;
1378
1379 local_irq_save(flags);
1380 debug_check_no_locks_freed(x, s->object_size);
1381 local_irq_restore(flags);
1382 }
1383#endif
1384 if (!(s->flags & SLAB_DEBUG_OBJECTS))
1385 debug_check_no_obj_freed(x, s->object_size);
1386
1387 /* KASAN might put x into memory quarantine, delaying its reuse */
1388 return kasan_slab_free(s, x, _RET_IP_);
1389}
1390
1391static inline bool slab_free_freelist_hook(struct kmem_cache *s,
1392 void **head, void **tail)
1393{
1394/*
1395 * Compiler cannot detect this function can be removed if slab_free_hook()
1396 * evaluates to nothing. Thus, catch all relevant config debug options here.
1397 */
1398#if defined(CONFIG_LOCKDEP) || \
1399 defined(CONFIG_DEBUG_KMEMLEAK) || \
1400 defined(CONFIG_DEBUG_OBJECTS_FREE) || \
1401 defined(CONFIG_KASAN)
1402
1403 void *object;
1404 void *next = *head;
1405 void *old_tail = *tail ? *tail : *head;
1406
1407 /* Head and tail of the reconstructed freelist */
1408 *head = NULL;
1409 *tail = NULL;
1410
1411 do {
1412 object = next;
1413 next = get_freepointer(s, object);
1414 /* If object's reuse doesn't have to be delayed */
1415 if (!slab_free_hook(s, object)) {
1416 /* Move object to the new freelist */
1417 set_freepointer(s, object, *head);
1418 *head = object;
1419 if (!*tail)
1420 *tail = object;
1421 }
1422 } while (object != old_tail);
1423
1424 if (*head == *tail)
1425 *tail = NULL;
1426
1427 return *head != NULL;
1428#else
1429 return true;
1430#endif
1431}
1432
1433static void setup_object(struct kmem_cache *s, struct page *page,
1434 void *object)
1435{
1436 setup_object_debug(s, page, object);
1437 kasan_init_slab_obj(s, object);
1438 if (unlikely(s->ctor)) {
1439 kasan_unpoison_object_data(s, object);
1440 s->ctor(object);
1441 kasan_poison_object_data(s, object);
1442 }
1443}
1444
1445/*
1446 * Slab allocation and freeing
1447 */
1448static inline struct page *alloc_slab_page(struct kmem_cache *s,
1449 gfp_t flags, int node, struct kmem_cache_order_objects oo)
1450{
1451 struct page *page;
1452 unsigned int order = oo_order(oo);
1453
1454 if (node == NUMA_NO_NODE)
1455 page = alloc_pages(flags, order);
1456 else
1457 page = __alloc_pages_node(node, flags, order);
1458
1459 if (page && memcg_charge_slab(page, flags, order, s)) {
1460 __free_pages(page, order);
1461 page = NULL;
1462 }
1463
1464 return page;
1465}
1466
1467#ifdef CONFIG_SLAB_FREELIST_RANDOM
1468/* Pre-initialize the random sequence cache */
1469static int init_cache_random_seq(struct kmem_cache *s)
1470{
1471 unsigned int count = oo_objects(s->oo);
1472 int err;
1473
1474 /* Bailout if already initialised */
1475 if (s->random_seq)
1476 return 0;
1477
1478 err = cache_random_seq_create(s, count, GFP_KERNEL);
1479 if (err) {
1480 pr_err("SLUB: Unable to initialize free list for %s\n",
1481 s->name);
1482 return err;
1483 }
1484
1485 /* Transform to an offset on the set of pages */
1486 if (s->random_seq) {
1487 unsigned int i;
1488
1489 for (i = 0; i < count; i++)
1490 s->random_seq[i] *= s->size;
1491 }
1492 return 0;
1493}
1494
1495/* Initialize each random sequence freelist per cache */
1496static void __init init_freelist_randomization(void)
1497{
1498 struct kmem_cache *s;
1499
1500 mutex_lock(&slab_mutex);
1501
1502 list_for_each_entry(s, &slab_caches, list)
1503 init_cache_random_seq(s);
1504
1505 mutex_unlock(&slab_mutex);
1506}
1507
1508/* Get the next entry on the pre-computed freelist randomized */
1509static void *next_freelist_entry(struct kmem_cache *s, struct page *page,
1510 unsigned long *pos, void *start,
1511 unsigned long page_limit,
1512 unsigned long freelist_count)
1513{
1514 unsigned int idx;
1515
1516 /*
1517 * If the target page allocation failed, the number of objects on the
1518 * page might be smaller than the usual size defined by the cache.
1519 */
1520 do {
1521 idx = s->random_seq[*pos];
1522 *pos += 1;
1523 if (*pos >= freelist_count)
1524 *pos = 0;
1525 } while (unlikely(idx >= page_limit));
1526
1527 return (char *)start + idx;
1528}
1529
1530/* Shuffle the single linked freelist based on a random pre-computed sequence */
1531static bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1532{
1533 void *start;
1534 void *cur;
1535 void *next;
1536 unsigned long idx, pos, page_limit, freelist_count;
1537
1538 if (page->objects < 2 || !s->random_seq)
1539 return false;
1540
1541 freelist_count = oo_objects(s->oo);
1542 pos = get_random_int() % freelist_count;
1543
1544 page_limit = page->objects * s->size;
1545 start = fixup_red_left(s, page_address(page));
1546
1547 /* First entry is used as the base of the freelist */
1548 cur = next_freelist_entry(s, page, &pos, start, page_limit,
1549 freelist_count);
1550 page->freelist = cur;
1551
1552 for (idx = 1; idx < page->objects; idx++) {
1553 setup_object(s, page, cur);
1554 next = next_freelist_entry(s, page, &pos, start, page_limit,
1555 freelist_count);
1556 set_freepointer(s, cur, next);
1557 cur = next;
1558 }
1559 setup_object(s, page, cur);
1560 set_freepointer(s, cur, NULL);
1561
1562 return true;
1563}
1564#else
1565static inline int init_cache_random_seq(struct kmem_cache *s)
1566{
1567 return 0;
1568}
1569static inline void init_freelist_randomization(void) { }
1570static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page)
1571{
1572 return false;
1573}
1574#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1575
1576static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1577{
1578 struct page *page;
1579 struct kmem_cache_order_objects oo = s->oo;
1580 gfp_t alloc_gfp;
1581 void *start, *p;
1582 int idx, order;
1583 bool shuffle;
1584
1585 flags &= gfp_allowed_mask;
1586
1587 if (gfpflags_allow_blocking(flags))
1588 local_irq_enable();
1589
1590 flags |= s->allocflags;
1591
1592 /*
1593 * Let the initial higher-order allocation fail under memory pressure
1594 * so we fall-back to the minimum order allocation.
1595 */
1596 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
1597 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
1598 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
1599
1600 page = alloc_slab_page(s, alloc_gfp, node, oo);
1601 if (unlikely(!page)) {
1602 oo = s->min;
1603 alloc_gfp = flags;
1604 /*
1605 * Allocation may have failed due to fragmentation.
1606 * Try a lower order alloc if possible
1607 */
1608 page = alloc_slab_page(s, alloc_gfp, node, oo);
1609 if (unlikely(!page))
1610 goto out;
1611 stat(s, ORDER_FALLBACK);
1612 }
1613
1614 page->objects = oo_objects(oo);
1615
1616 order = compound_order(page);
1617 page->slab_cache = s;
1618 __SetPageSlab(page);
1619 if (page_is_pfmemalloc(page))
1620 SetPageSlabPfmemalloc(page);
1621
1622 start = page_address(page);
1623
1624 if (unlikely(s->flags & SLAB_POISON))
1625 memset(start, POISON_INUSE, PAGE_SIZE << order);
1626
1627 kasan_poison_slab(page);
1628
1629 shuffle = shuffle_freelist(s, page);
1630
1631 if (!shuffle) {
1632 for_each_object_idx(p, idx, s, start, page->objects) {
1633 setup_object(s, page, p);
1634 if (likely(idx < page->objects))
1635 set_freepointer(s, p, p + s->size);
1636 else
1637 set_freepointer(s, p, NULL);
1638 }
1639 page->freelist = fixup_red_left(s, start);
1640 }
1641
1642 page->inuse = page->objects;
1643 page->frozen = 1;
1644
1645out:
1646 if (gfpflags_allow_blocking(flags))
1647 local_irq_disable();
1648 if (!page)
1649 return NULL;
1650
1651 mod_lruvec_page_state(page,
1652 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1653 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1654 1 << oo_order(oo));
1655
1656 inc_slabs_node(s, page_to_nid(page), page->objects);
1657
1658 return page;
1659}
1660
1661static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
1662{
1663 if (unlikely(flags & GFP_SLAB_BUG_MASK)) {
1664 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
1665 flags &= ~GFP_SLAB_BUG_MASK;
1666 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
1667 invalid_mask, &invalid_mask, flags, &flags);
1668 dump_stack();
1669 }
1670
1671 return allocate_slab(s,
1672 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1673}
1674
1675static void __free_slab(struct kmem_cache *s, struct page *page)
1676{
1677 int order = compound_order(page);
1678 int pages = 1 << order;
1679
1680 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1681 void *p;
1682
1683 slab_pad_check(s, page);
1684 for_each_object(p, s, page_address(page),
1685 page->objects)
1686 check_object(s, page, p, SLUB_RED_INACTIVE);
1687 }
1688
1689 mod_lruvec_page_state(page,
1690 (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1691 NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1692 -pages);
1693
1694 __ClearPageSlabPfmemalloc(page);
1695 __ClearPageSlab(page);
1696
1697 page_mapcount_reset(page);
1698 if (current->reclaim_state)
1699 current->reclaim_state->reclaimed_slab += pages;
1700 memcg_uncharge_slab(page, order, s);
1701 __free_pages(page, order);
1702}
1703
1704#define need_reserve_slab_rcu \
1705 (sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
1706
1707static void rcu_free_slab(struct rcu_head *h)
1708{
1709 struct page *page;
1710
1711 if (need_reserve_slab_rcu)
1712 page = virt_to_head_page(h);
1713 else
1714 page = container_of((struct list_head *)h, struct page, lru);
1715
1716 __free_slab(page->slab_cache, page);
1717}
1718
1719static void free_slab(struct kmem_cache *s, struct page *page)
1720{
1721 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
1722 struct rcu_head *head;
1723
1724 if (need_reserve_slab_rcu) {
1725 int order = compound_order(page);
1726 int offset = (PAGE_SIZE << order) - s->reserved;
1727
1728 VM_BUG_ON(s->reserved != sizeof(*head));
1729 head = page_address(page) + offset;
1730 } else {
1731 head = &page->rcu_head;
1732 }
1733
1734 call_rcu(head, rcu_free_slab);
1735 } else
1736 __free_slab(s, page);
1737}
1738
1739static void discard_slab(struct kmem_cache *s, struct page *page)
1740{
1741 dec_slabs_node(s, page_to_nid(page), page->objects);
1742 free_slab(s, page);
1743}
1744
1745/*
1746 * Management of partially allocated slabs.
1747 */
1748static inline void
1749__add_partial(struct kmem_cache_node *n, struct page *page, int tail)
1750{
1751 n->nr_partial++;
1752 if (tail == DEACTIVATE_TO_TAIL)
1753 list_add_tail(&page->lru, &n->partial);
1754 else
1755 list_add(&page->lru, &n->partial);
1756}
1757
1758static inline void add_partial(struct kmem_cache_node *n,
1759 struct page *page, int tail)
1760{
1761 lockdep_assert_held(&n->list_lock);
1762 __add_partial(n, page, tail);
1763}
1764
1765static inline void remove_partial(struct kmem_cache_node *n,
1766 struct page *page)
1767{
1768 lockdep_assert_held(&n->list_lock);
1769 list_del(&page->lru);
1770 n->nr_partial--;
1771}
1772
1773/*
1774 * Remove slab from the partial list, freeze it and
1775 * return the pointer to the freelist.
1776 *
1777 * Returns a list of objects or NULL if it fails.
1778 */
1779static inline void *acquire_slab(struct kmem_cache *s,
1780 struct kmem_cache_node *n, struct page *page,
1781 int mode, int *objects)
1782{
1783 void *freelist;
1784 unsigned long counters;
1785 struct page new;
1786
1787 lockdep_assert_held(&n->list_lock);
1788
1789 /*
1790 * Zap the freelist and set the frozen bit.
1791 * The old freelist is the list of objects for the
1792 * per cpu allocation list.
1793 */
1794 freelist = page->freelist;
1795 counters = page->counters;
1796 new.counters = counters;
1797 *objects = new.objects - new.inuse;
1798 if (mode) {
1799 new.inuse = page->objects;
1800 new.freelist = NULL;
1801 } else {
1802 new.freelist = freelist;
1803 }
1804
1805 VM_BUG_ON(new.frozen);
1806 new.frozen = 1;
1807
1808 if (!__cmpxchg_double_slab(s, page,
1809 freelist, counters,
1810 new.freelist, new.counters,
1811 "acquire_slab"))
1812 return NULL;
1813
1814 remove_partial(n, page);
1815 WARN_ON(!freelist);
1816 return freelist;
1817}
1818
1819static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
1820static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags);
1821
1822/*
1823 * Try to allocate a partial slab from a specific node.
1824 */
1825static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
1826 struct kmem_cache_cpu *c, gfp_t flags)
1827{
1828 struct page *page, *page2;
1829 void *object = NULL;
1830 unsigned int available = 0;
1831 int objects;
1832
1833 /*
1834 * Racy check. If we mistakenly see no partial slabs then we
1835 * just allocate an empty slab. If we mistakenly try to get a
1836 * partial slab and there is none available then get_partials()
1837 * will return NULL.
1838 */
1839 if (!n || !n->nr_partial)
1840 return NULL;
1841
1842 spin_lock(&n->list_lock);
1843 list_for_each_entry_safe(page, page2, &n->partial, lru) {
1844 void *t;
1845
1846 if (!pfmemalloc_match(page, flags))
1847 continue;
1848
1849 t = acquire_slab(s, n, page, object == NULL, &objects);
1850 if (!t)
1851 break;
1852
1853 available += objects;
1854 if (!object) {
1855 c->page = page;
1856 stat(s, ALLOC_FROM_PARTIAL);
1857 object = t;
1858 } else {
1859 put_cpu_partial(s, page, 0);
1860 stat(s, CPU_PARTIAL_NODE);
1861 }
1862 if (!kmem_cache_has_cpu_partial(s)
1863 || available > slub_cpu_partial(s) / 2)
1864 break;
1865
1866 }
1867 spin_unlock(&n->list_lock);
1868 return object;
1869}
1870
1871/*
1872 * Get a page from somewhere. Search in increasing NUMA distances.
1873 */
1874static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1875 struct kmem_cache_cpu *c)
1876{
1877#ifdef CONFIG_NUMA
1878 struct zonelist *zonelist;
1879 struct zoneref *z;
1880 struct zone *zone;
1881 enum zone_type high_zoneidx = gfp_zone(flags);
1882 void *object;
1883 unsigned int cpuset_mems_cookie;
1884
1885 /*
1886 * The defrag ratio allows a configuration of the tradeoffs between
1887 * inter node defragmentation and node local allocations. A lower
1888 * defrag_ratio increases the tendency to do local allocations
1889 * instead of attempting to obtain partial slabs from other nodes.
1890 *
1891 * If the defrag_ratio is set to 0 then kmalloc() always
1892 * returns node local objects. If the ratio is higher then kmalloc()
1893 * may return off node objects because partial slabs are obtained
1894 * from other nodes and filled up.
1895 *
1896 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
1897 * (which makes defrag_ratio = 1000) then every (well almost)
1898 * allocation will first attempt to defrag slab caches on other nodes.
1899 * This means scanning over all nodes to look for partial slabs which
1900 * may be expensive if we do it every time we are trying to find a slab
1901 * with available objects.
1902 */
1903 if (!s->remote_node_defrag_ratio ||
1904 get_cycles() % 1024 > s->remote_node_defrag_ratio)
1905 return NULL;
1906
1907 do {
1908 cpuset_mems_cookie = read_mems_allowed_begin();
1909 zonelist = node_zonelist(mempolicy_slab_node(), flags);
1910 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1911 struct kmem_cache_node *n;
1912
1913 n = get_node(s, zone_to_nid(zone));
1914
1915 if (n && cpuset_zone_allowed(zone, flags) &&
1916 n->nr_partial > s->min_partial) {
1917 object = get_partial_node(s, n, c, flags);
1918 if (object) {
1919 /*
1920 * Don't check read_mems_allowed_retry()
1921 * here - if mems_allowed was updated in
1922 * parallel, that was a harmless race
1923 * between allocation and the cpuset
1924 * update
1925 */
1926 return object;
1927 }
1928 }
1929 }
1930 } while (read_mems_allowed_retry(cpuset_mems_cookie));
1931#endif
1932 return NULL;
1933}
1934
1935/*
1936 * Get a partial page, lock it and return it.
1937 */
1938static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1939 struct kmem_cache_cpu *c)
1940{
1941 void *object;
1942 int searchnode = node;
1943
1944 if (node == NUMA_NO_NODE)
1945 searchnode = numa_mem_id();
1946 else if (!node_present_pages(node))
1947 searchnode = node_to_mem_node(node);
1948
1949 object = get_partial_node(s, get_node(s, searchnode), c, flags);
1950 if (object || node != NUMA_NO_NODE)
1951 return object;
1952
1953 return get_any_partial(s, flags, c);
1954}
1955
1956#ifdef CONFIG_PREEMPT
1957/*
1958 * Calculate the next globally unique transaction for disambiguiation
1959 * during cmpxchg. The transactions start with the cpu number and are then
1960 * incremented by CONFIG_NR_CPUS.
1961 */
1962#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
1963#else
1964/*
1965 * No preemption supported therefore also no need to check for
1966 * different cpus.
1967 */
1968#define TID_STEP 1
1969#endif
1970
1971static inline unsigned long next_tid(unsigned long tid)
1972{
1973 return tid + TID_STEP;
1974}
1975
1976static inline unsigned int tid_to_cpu(unsigned long tid)
1977{
1978 return tid % TID_STEP;
1979}
1980
1981static inline unsigned long tid_to_event(unsigned long tid)
1982{
1983 return tid / TID_STEP;
1984}
1985
1986static inline unsigned int init_tid(int cpu)
1987{
1988 return cpu;
1989}
1990
1991static inline void note_cmpxchg_failure(const char *n,
1992 const struct kmem_cache *s, unsigned long tid)
1993{
1994#ifdef SLUB_DEBUG_CMPXCHG
1995 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1996
1997 pr_info("%s %s: cmpxchg redo ", n, s->name);
1998
1999#ifdef CONFIG_PREEMPT
2000 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2001 pr_warn("due to cpu change %d -> %d\n",
2002 tid_to_cpu(tid), tid_to_cpu(actual_tid));
2003 else
2004#endif
2005 if (tid_to_event(tid) != tid_to_event(actual_tid))
2006 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2007 tid_to_event(tid), tid_to_event(actual_tid));
2008 else
2009 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2010 actual_tid, tid, next_tid(tid));
2011#endif
2012 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2013}
2014
2015static void init_kmem_cache_cpus(struct kmem_cache *s)
2016{
2017 int cpu;
2018
2019 for_each_possible_cpu(cpu)
2020 per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
2021}
2022
2023/*
2024 * Remove the cpu slab
2025 */
2026static void deactivate_slab(struct kmem_cache *s, struct page *page,
2027 void *freelist, struct kmem_cache_cpu *c)
2028{
2029 enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
2030 struct kmem_cache_node *n = get_node(s, page_to_nid(page));
2031 int lock = 0;
2032 enum slab_modes l = M_NONE, m = M_NONE;
2033 void *nextfree;
2034 int tail = DEACTIVATE_TO_HEAD;
2035 struct page new;
2036 struct page old;
2037
2038 if (page->freelist) {
2039 stat(s, DEACTIVATE_REMOTE_FREES);
2040 tail = DEACTIVATE_TO_TAIL;
2041 }
2042
2043 /*
2044 * Stage one: Free all available per cpu objects back
2045 * to the page freelist while it is still frozen. Leave the
2046 * last one.
2047 *
2048 * There is no need to take the list->lock because the page
2049 * is still frozen.
2050 */
2051 while (freelist && (nextfree = get_freepointer(s, freelist))) {
2052 void *prior;
2053 unsigned long counters;
2054
2055 do {
2056 prior = page->freelist;
2057 counters = page->counters;
2058 set_freepointer(s, freelist, prior);
2059 new.counters = counters;
2060 new.inuse--;
2061 VM_BUG_ON(!new.frozen);
2062
2063 } while (!__cmpxchg_double_slab(s, page,
2064 prior, counters,
2065 freelist, new.counters,
2066 "drain percpu freelist"));
2067
2068 freelist = nextfree;
2069 }
2070
2071 /*
2072 * Stage two: Ensure that the page is unfrozen while the
2073 * list presence reflects the actual number of objects
2074 * during unfreeze.
2075 *
2076 * We setup the list membership and then perform a cmpxchg
2077 * with the count. If there is a mismatch then the page
2078 * is not unfrozen but the page is on the wrong list.
2079 *
2080 * Then we restart the process which may have to remove
2081 * the page from the list that we just put it on again
2082 * because the number of objects in the slab may have
2083 * changed.
2084 */
2085redo:
2086
2087 old.freelist = page->freelist;
2088 old.counters = page->counters;
2089 VM_BUG_ON(!old.frozen);
2090
2091 /* Determine target state of the slab */
2092 new.counters = old.counters;
2093 if (freelist) {
2094 new.inuse--;
2095 set_freepointer(s, freelist, old.freelist);
2096 new.freelist = freelist;
2097 } else
2098 new.freelist = old.freelist;
2099
2100 new.frozen = 0;
2101
2102 if (!new.inuse && n->nr_partial >= s->min_partial)
2103 m = M_FREE;
2104 else if (new.freelist) {
2105 m = M_PARTIAL;
2106 if (!lock) {
2107 lock = 1;
2108 /*
2109 * Taking the spinlock removes the possiblity
2110 * that acquire_slab() will see a slab page that
2111 * is frozen
2112 */
2113 spin_lock(&n->list_lock);
2114 }
2115 } else {
2116 m = M_FULL;
2117 if (kmem_cache_debug(s) && !lock) {
2118 lock = 1;
2119 /*
2120 * This also ensures that the scanning of full
2121 * slabs from diagnostic functions will not see
2122 * any frozen slabs.
2123 */
2124 spin_lock(&n->list_lock);
2125 }
2126 }
2127
2128 if (l != m) {
2129
2130 if (l == M_PARTIAL)
2131
2132 remove_partial(n, page);
2133
2134 else if (l == M_FULL)
2135
2136 remove_full(s, n, page);
2137
2138 if (m == M_PARTIAL) {
2139
2140 add_partial(n, page, tail);
2141 stat(s, tail);
2142
2143 } else if (m == M_FULL) {
2144
2145 stat(s, DEACTIVATE_FULL);
2146 add_full(s, n, page);
2147
2148 }
2149 }
2150
2151 l = m;
2152 if (!__cmpxchg_double_slab(s, page,
2153 old.freelist, old.counters,
2154 new.freelist, new.counters,
2155 "unfreezing slab"))
2156 goto redo;
2157
2158 if (lock)
2159 spin_unlock(&n->list_lock);
2160
2161 if (m == M_FREE) {
2162 stat(s, DEACTIVATE_EMPTY);
2163 discard_slab(s, page);
2164 stat(s, FREE_SLAB);
2165 }
2166
2167 c->page = NULL;
2168 c->freelist = NULL;
2169}
2170
2171/*
2172 * Unfreeze all the cpu partial slabs.
2173 *
2174 * This function must be called with interrupts disabled
2175 * for the cpu using c (or some other guarantee must be there
2176 * to guarantee no concurrent accesses).
2177 */
2178static void unfreeze_partials(struct kmem_cache *s,
2179 struct kmem_cache_cpu *c)
2180{
2181#ifdef CONFIG_SLUB_CPU_PARTIAL
2182 struct kmem_cache_node *n = NULL, *n2 = NULL;
2183 struct page *page, *discard_page = NULL;
2184
2185 while ((page = c->partial)) {
2186 struct page new;
2187 struct page old;
2188
2189 c->partial = page->next;
2190
2191 n2 = get_node(s, page_to_nid(page));
2192 if (n != n2) {
2193 if (n)
2194 spin_unlock(&n->list_lock);
2195
2196 n = n2;
2197 spin_lock(&n->list_lock);
2198 }
2199
2200 do {
2201
2202 old.freelist = page->freelist;
2203 old.counters = page->counters;
2204 VM_BUG_ON(!old.frozen);
2205
2206 new.counters = old.counters;
2207 new.freelist = old.freelist;
2208
2209 new.frozen = 0;
2210
2211 } while (!__cmpxchg_double_slab(s, page,
2212 old.freelist, old.counters,
2213 new.freelist, new.counters,
2214 "unfreezing slab"));
2215
2216 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
2217 page->next = discard_page;
2218 discard_page = page;
2219 } else {
2220 add_partial(n, page, DEACTIVATE_TO_TAIL);
2221 stat(s, FREE_ADD_PARTIAL);
2222 }
2223 }
2224
2225 if (n)
2226 spin_unlock(&n->list_lock);
2227
2228 while (discard_page) {
2229 page = discard_page;
2230 discard_page = discard_page->next;
2231
2232 stat(s, DEACTIVATE_EMPTY);
2233 discard_slab(s, page);
2234 stat(s, FREE_SLAB);
2235 }
2236#endif
2237}
2238
2239/*
2240 * Put a page that was just frozen (in __slab_free) into a partial page
2241 * slot if available.
2242 *
2243 * If we did not find a slot then simply move all the partials to the
2244 * per node partial list.
2245 */
2246static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
2247{
2248#ifdef CONFIG_SLUB_CPU_PARTIAL
2249 struct page *oldpage;
2250 int pages;
2251 int pobjects;
2252
2253 preempt_disable();
2254 do {
2255 pages = 0;
2256 pobjects = 0;
2257 oldpage = this_cpu_read(s->cpu_slab->partial);
2258
2259 if (oldpage) {
2260 pobjects = oldpage->pobjects;
2261 pages = oldpage->pages;
2262 if (drain && pobjects > s->cpu_partial) {
2263 unsigned long flags;
2264 /*
2265 * partial array is full. Move the existing
2266 * set to the per node partial list.
2267 */
2268 local_irq_save(flags);
2269 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2270 local_irq_restore(flags);
2271 oldpage = NULL;
2272 pobjects = 0;
2273 pages = 0;
2274 stat(s, CPU_PARTIAL_DRAIN);
2275 }
2276 }
2277
2278 pages++;
2279 pobjects += page->objects - page->inuse;
2280
2281 page->pages = pages;
2282 page->pobjects = pobjects;
2283 page->next = oldpage;
2284
2285 } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page)
2286 != oldpage);
2287 if (unlikely(!s->cpu_partial)) {
2288 unsigned long flags;
2289
2290 local_irq_save(flags);
2291 unfreeze_partials(s, this_cpu_ptr(s->cpu_slab));
2292 local_irq_restore(flags);
2293 }
2294 preempt_enable();
2295#endif
2296}
2297
2298static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2299{
2300 stat(s, CPUSLAB_FLUSH);
2301 deactivate_slab(s, c->page, c->freelist, c);
2302
2303 c->tid = next_tid(c->tid);
2304}
2305
2306/*
2307 * Flush cpu slab.
2308 *
2309 * Called from IPI handler with interrupts disabled.
2310 */
2311static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2312{
2313 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2314
2315 if (likely(c)) {
2316 if (c->page)
2317 flush_slab(s, c);
2318
2319 unfreeze_partials(s, c);
2320 }
2321}
2322
2323static void flush_cpu_slab(void *d)
2324{
2325 struct kmem_cache *s = d;
2326
2327 __flush_cpu_slab(s, smp_processor_id());
2328}
2329
2330static bool has_cpu_slab(int cpu, void *info)
2331{
2332 struct kmem_cache *s = info;
2333 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2334
2335 return c->page || slub_percpu_partial(c);
2336}
2337
2338static void flush_all(struct kmem_cache *s)
2339{
2340 on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
2341}
2342
2343/*
2344 * Use the cpu notifier to insure that the cpu slabs are flushed when
2345 * necessary.
2346 */
2347static int slub_cpu_dead(unsigned int cpu)
2348{
2349 struct kmem_cache *s;
2350 unsigned long flags;
2351
2352 mutex_lock(&slab_mutex);
2353 list_for_each_entry(s, &slab_caches, list) {
2354 local_irq_save(flags);
2355 __flush_cpu_slab(s, cpu);
2356 local_irq_restore(flags);
2357 }
2358 mutex_unlock(&slab_mutex);
2359 return 0;
2360}
2361
2362/*
2363 * Check if the objects in a per cpu structure fit numa
2364 * locality expectations.
2365 */
2366static inline int node_match(struct page *page, int node)
2367{
2368#ifdef CONFIG_NUMA
2369 if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
2370 return 0;
2371#endif
2372 return 1;
2373}
2374
2375#ifdef CONFIG_SLUB_DEBUG
2376static int count_free(struct page *page)
2377{
2378 return page->objects - page->inuse;
2379}
2380
2381static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2382{
2383 return atomic_long_read(&n->total_objects);
2384}
2385#endif /* CONFIG_SLUB_DEBUG */
2386
2387#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
2388static unsigned long count_partial(struct kmem_cache_node *n,
2389 int (*get_count)(struct page *))
2390{
2391 unsigned long flags;
2392 unsigned long x = 0;
2393 struct page *page;
2394
2395 spin_lock_irqsave(&n->list_lock, flags);
2396 list_for_each_entry(page, &n->partial, lru)
2397 x += get_count(page);
2398 spin_unlock_irqrestore(&n->list_lock, flags);
2399 return x;
2400}
2401#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
2402
2403static noinline void
2404slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2405{
2406#ifdef CONFIG_SLUB_DEBUG
2407 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
2408 DEFAULT_RATELIMIT_BURST);
2409 int node;
2410 struct kmem_cache_node *n;
2411
2412 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
2413 return;
2414
2415 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
2416 nid, gfpflags, &gfpflags);
2417 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
2418 s->name, s->object_size, s->size, oo_order(s->oo),
2419 oo_order(s->min));
2420
2421 if (oo_order(s->min) > get_order(s->object_size))
2422 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
2423 s->name);
2424
2425 for_each_kmem_cache_node(s, node, n) {
2426 unsigned long nr_slabs;
2427 unsigned long nr_objs;
2428 unsigned long nr_free;
2429
2430 nr_free = count_partial(n, count_free);
2431 nr_slabs = node_nr_slabs(n);
2432 nr_objs = node_nr_objs(n);
2433
2434 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
2435 node, nr_slabs, nr_objs, nr_free);
2436 }
2437#endif
2438}
2439
2440static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2441 int node, struct kmem_cache_cpu **pc)
2442{
2443 void *freelist;
2444 struct kmem_cache_cpu *c = *pc;
2445 struct page *page;
2446
2447 freelist = get_partial(s, flags, node, c);
2448
2449 if (freelist)
2450 return freelist;
2451
2452 page = new_slab(s, flags, node);
2453 if (page) {
2454 c = raw_cpu_ptr(s->cpu_slab);
2455 if (c->page)
2456 flush_slab(s, c);
2457
2458 /*
2459 * No other reference to the page yet so we can
2460 * muck around with it freely without cmpxchg
2461 */
2462 freelist = page->freelist;
2463 page->freelist = NULL;
2464
2465 stat(s, ALLOC_SLAB);
2466 c->page = page;
2467 *pc = c;
2468 } else
2469 freelist = NULL;
2470
2471 return freelist;
2472}
2473
2474static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags)
2475{
2476 if (unlikely(PageSlabPfmemalloc(page)))
2477 return gfp_pfmemalloc_allowed(gfpflags);
2478
2479 return true;
2480}
2481
2482/*
2483 * Check the page->freelist of a page and either transfer the freelist to the
2484 * per cpu freelist or deactivate the page.
2485 *
2486 * The page is still frozen if the return value is not NULL.
2487 *
2488 * If this function returns NULL then the page has been unfrozen.
2489 *
2490 * This function must be called with interrupt disabled.
2491 */
2492static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2493{
2494 struct page new;
2495 unsigned long counters;
2496 void *freelist;
2497
2498 do {
2499 freelist = page->freelist;
2500 counters = page->counters;
2501
2502 new.counters = counters;
2503 VM_BUG_ON(!new.frozen);
2504
2505 new.inuse = page->objects;
2506 new.frozen = freelist != NULL;
2507
2508 } while (!__cmpxchg_double_slab(s, page,
2509 freelist, counters,
2510 NULL, new.counters,
2511 "get_freelist"));
2512
2513 return freelist;
2514}
2515
2516/*
2517 * Slow path. The lockless freelist is empty or we need to perform
2518 * debugging duties.
2519 *
2520 * Processing is still very fast if new objects have been freed to the
2521 * regular freelist. In that case we simply take over the regular freelist
2522 * as the lockless freelist and zap the regular freelist.
2523 *
2524 * If that is not working then we fall back to the partial lists. We take the
2525 * first element of the freelist as the object to allocate now and move the
2526 * rest of the freelist to the lockless freelist.
2527 *
2528 * And if we were unable to get a new slab from the partial slab lists then
2529 * we need to allocate a new slab. This is the slowest path since it involves
2530 * a call to the page allocator and the setup of a new slab.
2531 *
2532 * Version of __slab_alloc to use when we know that interrupts are
2533 * already disabled (which is the case for bulk allocation).
2534 */
2535static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2536 unsigned long addr, struct kmem_cache_cpu *c)
2537{
2538 void *freelist;
2539 struct page *page;
2540
2541 page = c->page;
2542 if (!page)
2543 goto new_slab;
2544redo:
2545
2546 if (unlikely(!node_match(page, node))) {
2547 int searchnode = node;
2548
2549 if (node != NUMA_NO_NODE && !node_present_pages(node))
2550 searchnode = node_to_mem_node(node);
2551
2552 if (unlikely(!node_match(page, searchnode))) {
2553 stat(s, ALLOC_NODE_MISMATCH);
2554 deactivate_slab(s, page, c->freelist, c);
2555 goto new_slab;
2556 }
2557 }
2558
2559 /*
2560 * By rights, we should be searching for a slab page that was
2561 * PFMEMALLOC but right now, we are losing the pfmemalloc
2562 * information when the page leaves the per-cpu allocator
2563 */
2564 if (unlikely(!pfmemalloc_match(page, gfpflags))) {
2565 deactivate_slab(s, page, c->freelist, c);
2566 goto new_slab;
2567 }
2568
2569 /* must check again c->freelist in case of cpu migration or IRQ */
2570 freelist = c->freelist;
2571 if (freelist)
2572 goto load_freelist;
2573
2574 freelist = get_freelist(s, page);
2575
2576 if (!freelist) {
2577 c->page = NULL;
2578 stat(s, DEACTIVATE_BYPASS);
2579 goto new_slab;
2580 }
2581
2582 stat(s, ALLOC_REFILL);
2583
2584load_freelist:
2585 /*
2586 * freelist is pointing to the list of objects to be used.
2587 * page is pointing to the page from which the objects are obtained.
2588 * That page must be frozen for per cpu allocations to work.
2589 */
2590 VM_BUG_ON(!c->page->frozen);
2591 c->freelist = get_freepointer(s, freelist);
2592 c->tid = next_tid(c->tid);
2593 return freelist;
2594
2595new_slab:
2596
2597 if (slub_percpu_partial(c)) {
2598 page = c->page = slub_percpu_partial(c);
2599 slub_set_percpu_partial(c, page);
2600 stat(s, CPU_PARTIAL_ALLOC);
2601 goto redo;
2602 }
2603
2604 freelist = new_slab_objects(s, gfpflags, node, &c);
2605
2606 if (unlikely(!freelist)) {
2607 slab_out_of_memory(s, gfpflags, node);
2608 return NULL;
2609 }
2610
2611 page = c->page;
2612 if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags)))
2613 goto load_freelist;
2614
2615 /* Only entered in the debug case */
2616 if (kmem_cache_debug(s) &&
2617 !alloc_debug_processing(s, page, freelist, addr))
2618 goto new_slab; /* Slab failed checks. Next slab needed */
2619
2620 deactivate_slab(s, page, get_freepointer(s, freelist), c);
2621 return freelist;
2622}
2623
2624/*
2625 * Another one that disabled interrupt and compensates for possible
2626 * cpu changes by refetching the per cpu area pointer.
2627 */
2628static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2629 unsigned long addr, struct kmem_cache_cpu *c)
2630{
2631 void *p;
2632 unsigned long flags;
2633
2634 local_irq_save(flags);
2635#ifdef CONFIG_PREEMPT
2636 /*
2637 * We may have been preempted and rescheduled on a different
2638 * cpu before disabling interrupts. Need to reload cpu area
2639 * pointer.
2640 */
2641 c = this_cpu_ptr(s->cpu_slab);
2642#endif
2643
2644 p = ___slab_alloc(s, gfpflags, node, addr, c);
2645 local_irq_restore(flags);
2646 return p;
2647}
2648
2649/*
2650 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2651 * have the fastpath folded into their functions. So no function call
2652 * overhead for requests that can be satisfied on the fastpath.
2653 *
2654 * The fastpath works by first checking if the lockless freelist can be used.
2655 * If not then __slab_alloc is called for slow processing.
2656 *
2657 * Otherwise we can simply pick the next object from the lockless free list.
2658 */
2659static __always_inline void *slab_alloc_node(struct kmem_cache *s,
2660 gfp_t gfpflags, int node, unsigned long addr)
2661{
2662 void *object;
2663 struct kmem_cache_cpu *c;
2664 struct page *page;
2665 unsigned long tid;
2666
2667 s = slab_pre_alloc_hook(s, gfpflags);
2668 if (!s)
2669 return NULL;
2670redo:
2671 /*
2672 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2673 * enabled. We may switch back and forth between cpus while
2674 * reading from one cpu area. That does not matter as long
2675 * as we end up on the original cpu again when doing the cmpxchg.
2676 *
2677 * We should guarantee that tid and kmem_cache are retrieved on
2678 * the same cpu. It could be different if CONFIG_PREEMPT so we need
2679 * to check if it is matched or not.
2680 */
2681 do {
2682 tid = this_cpu_read(s->cpu_slab->tid);
2683 c = raw_cpu_ptr(s->cpu_slab);
2684 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2685 unlikely(tid != READ_ONCE(c->tid)));
2686
2687 /*
2688 * Irqless object alloc/free algorithm used here depends on sequence
2689 * of fetching cpu_slab's data. tid should be fetched before anything
2690 * on c to guarantee that object and page associated with previous tid
2691 * won't be used with current tid. If we fetch tid first, object and
2692 * page could be one associated with next tid and our alloc/free
2693 * request will be failed. In this case, we will retry. So, no problem.
2694 */
2695 barrier();
2696
2697 /*
2698 * The transaction ids are globally unique per cpu and per operation on
2699 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2700 * occurs on the right processor and that there was no operation on the
2701 * linked list in between.
2702 */
2703
2704 object = c->freelist;
2705 page = c->page;
2706 if (unlikely(!object || !node_match(page, node))) {
2707 object = __slab_alloc(s, gfpflags, node, addr, c);
2708 stat(s, ALLOC_SLOWPATH);
2709 } else {
2710 void *next_object = get_freepointer_safe(s, object);
2711
2712 /*
2713 * The cmpxchg will only match if there was no additional
2714 * operation and if we are on the right processor.
2715 *
2716 * The cmpxchg does the following atomically (without lock
2717 * semantics!)
2718 * 1. Relocate first pointer to the current per cpu area.
2719 * 2. Verify that tid and freelist have not been changed
2720 * 3. If they were not changed replace tid and freelist
2721 *
2722 * Since this is without lock semantics the protection is only
2723 * against code executing on this cpu *not* from access by
2724 * other cpus.
2725 */
2726 if (unlikely(!this_cpu_cmpxchg_double(
2727 s->cpu_slab->freelist, s->cpu_slab->tid,
2728 object, tid,
2729 next_object, next_tid(tid)))) {
2730
2731 note_cmpxchg_failure("slab_alloc", s, tid);
2732 goto redo;
2733 }
2734 prefetch_freepointer(s, next_object);
2735 stat(s, ALLOC_FASTPATH);
2736 }
2737
2738 if (unlikely(gfpflags & __GFP_ZERO) && object)
2739 memset(object, 0, s->object_size);
2740
2741 slab_post_alloc_hook(s, gfpflags, 1, &object);
2742
2743 return object;
2744}
2745
2746static __always_inline void *slab_alloc(struct kmem_cache *s,
2747 gfp_t gfpflags, unsigned long addr)
2748{
2749 return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr);
2750}
2751
2752void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
2753{
2754 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2755
2756 trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size,
2757 s->size, gfpflags);
2758
2759 return ret;
2760}
2761EXPORT_SYMBOL(kmem_cache_alloc);
2762
2763#ifdef CONFIG_TRACING
2764void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
2765{
2766 void *ret = slab_alloc(s, gfpflags, _RET_IP_);
2767 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
2768 kasan_kmalloc(s, ret, size, gfpflags);
2769 return ret;
2770}
2771EXPORT_SYMBOL(kmem_cache_alloc_trace);
2772#endif
2773
2774#ifdef CONFIG_NUMA
2775void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
2776{
2777 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2778
2779 trace_kmem_cache_alloc_node(_RET_IP_, ret,
2780 s->object_size, s->size, gfpflags, node);
2781
2782 return ret;
2783}
2784EXPORT_SYMBOL(kmem_cache_alloc_node);
2785
2786#ifdef CONFIG_TRACING
2787void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2788 gfp_t gfpflags,
2789 int node, size_t size)
2790{
2791 void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_);
2792
2793 trace_kmalloc_node(_RET_IP_, ret,
2794 size, s->size, gfpflags, node);
2795
2796 kasan_kmalloc(s, ret, size, gfpflags);
2797 return ret;
2798}
2799EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2800#endif
2801#endif
2802
2803/*
2804 * Slow path handling. This may still be called frequently since objects
2805 * have a longer lifetime than the cpu slabs in most processing loads.
2806 *
2807 * So we still attempt to reduce cache line usage. Just take the slab
2808 * lock and free the item. If there is no additional partial page
2809 * handling required then we can return immediately.
2810 */
2811static void __slab_free(struct kmem_cache *s, struct page *page,
2812 void *head, void *tail, int cnt,
2813 unsigned long addr)
2814
2815{
2816 void *prior;
2817 int was_frozen;
2818 struct page new;
2819 unsigned long counters;
2820 struct kmem_cache_node *n = NULL;
2821 unsigned long uninitialized_var(flags);
2822
2823 stat(s, FREE_SLOWPATH);
2824
2825 if (kmem_cache_debug(s) &&
2826 !free_debug_processing(s, page, head, tail, cnt, addr))
2827 return;
2828
2829 do {
2830 if (unlikely(n)) {
2831 spin_unlock_irqrestore(&n->list_lock, flags);
2832 n = NULL;
2833 }
2834 prior = page->freelist;
2835 counters = page->counters;
2836 set_freepointer(s, tail, prior);
2837 new.counters = counters;
2838 was_frozen = new.frozen;
2839 new.inuse -= cnt;
2840 if ((!new.inuse || !prior) && !was_frozen) {
2841
2842 if (kmem_cache_has_cpu_partial(s) && !prior) {
2843
2844 /*
2845 * Slab was on no list before and will be
2846 * partially empty
2847 * We can defer the list move and instead
2848 * freeze it.
2849 */
2850 new.frozen = 1;
2851
2852 } else { /* Needs to be taken off a list */
2853
2854 n = get_node(s, page_to_nid(page));
2855 /*
2856 * Speculatively acquire the list_lock.
2857 * If the cmpxchg does not succeed then we may
2858 * drop the list_lock without any processing.
2859 *
2860 * Otherwise the list_lock will synchronize with
2861 * other processors updating the list of slabs.
2862 */
2863 spin_lock_irqsave(&n->list_lock, flags);
2864
2865 }
2866 }
2867
2868 } while (!cmpxchg_double_slab(s, page,
2869 prior, counters,
2870 head, new.counters,
2871 "__slab_free"));
2872
2873 if (likely(!n)) {
2874
2875 /*
2876 * If we just froze the page then put it onto the
2877 * per cpu partial list.
2878 */
2879 if (new.frozen && !was_frozen) {
2880 put_cpu_partial(s, page, 1);
2881 stat(s, CPU_PARTIAL_FREE);
2882 }
2883 /*
2884 * The list lock was not taken therefore no list
2885 * activity can be necessary.
2886 */
2887 if (was_frozen)
2888 stat(s, FREE_FROZEN);
2889 return;
2890 }
2891
2892 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
2893 goto slab_empty;
2894
2895 /*
2896 * Objects left in the slab. If it was not on the partial list before
2897 * then add it.
2898 */
2899 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
2900 if (kmem_cache_debug(s))
2901 remove_full(s, n, page);
2902 add_partial(n, page, DEACTIVATE_TO_TAIL);
2903 stat(s, FREE_ADD_PARTIAL);
2904 }
2905 spin_unlock_irqrestore(&n->list_lock, flags);
2906 return;
2907
2908slab_empty:
2909 if (prior) {
2910 /*
2911 * Slab on the partial list.
2912 */
2913 remove_partial(n, page);
2914 stat(s, FREE_REMOVE_PARTIAL);
2915 } else {
2916 /* Slab must be on the full list */
2917 remove_full(s, n, page);
2918 }
2919
2920 spin_unlock_irqrestore(&n->list_lock, flags);
2921 stat(s, FREE_SLAB);
2922 discard_slab(s, page);
2923}
2924
2925/*
2926 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2927 * can perform fastpath freeing without additional function calls.
2928 *
2929 * The fastpath is only possible if we are freeing to the current cpu slab
2930 * of this processor. This typically the case if we have just allocated
2931 * the item before.
2932 *
2933 * If fastpath is not possible then fall back to __slab_free where we deal
2934 * with all sorts of special processing.
2935 *
2936 * Bulk free of a freelist with several objects (all pointing to the
2937 * same page) possible by specifying head and tail ptr, plus objects
2938 * count (cnt). Bulk free indicated by tail pointer being set.
2939 */
2940static __always_inline void do_slab_free(struct kmem_cache *s,
2941 struct page *page, void *head, void *tail,
2942 int cnt, unsigned long addr)
2943{
2944 void *tail_obj = tail ? : head;
2945 struct kmem_cache_cpu *c;
2946 unsigned long tid;
2947redo:
2948 /*
2949 * Determine the currently cpus per cpu slab.
2950 * The cpu may change afterward. However that does not matter since
2951 * data is retrieved via this pointer. If we are on the same cpu
2952 * during the cmpxchg then the free will succeed.
2953 */
2954 do {
2955 tid = this_cpu_read(s->cpu_slab->tid);
2956 c = raw_cpu_ptr(s->cpu_slab);
2957 } while (IS_ENABLED(CONFIG_PREEMPT) &&
2958 unlikely(tid != READ_ONCE(c->tid)));
2959
2960 /* Same with comment on barrier() in slab_alloc_node() */
2961 barrier();
2962
2963 if (likely(page == c->page)) {
2964 set_freepointer(s, tail_obj, c->freelist);
2965
2966 if (unlikely(!this_cpu_cmpxchg_double(
2967 s->cpu_slab->freelist, s->cpu_slab->tid,
2968 c->freelist, tid,
2969 head, next_tid(tid)))) {
2970
2971 note_cmpxchg_failure("slab_free", s, tid);
2972 goto redo;
2973 }
2974 stat(s, FREE_FASTPATH);
2975 } else
2976 __slab_free(s, page, head, tail_obj, cnt, addr);
2977
2978}
2979
2980static __always_inline void slab_free(struct kmem_cache *s, struct page *page,
2981 void *head, void *tail, int cnt,
2982 unsigned long addr)
2983{
2984 /*
2985 * With KASAN enabled slab_free_freelist_hook modifies the freelist
2986 * to remove objects, whose reuse must be delayed.
2987 */
2988 if (slab_free_freelist_hook(s, &head, &tail))
2989 do_slab_free(s, page, head, tail, cnt, addr);
2990}
2991
2992#ifdef CONFIG_KASAN
2993void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
2994{
2995 do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr);
2996}
2997#endif
2998
2999void kmem_cache_free(struct kmem_cache *s, void *x)
3000{
3001 s = cache_from_obj(s, x);
3002 if (!s)
3003 return;
3004 slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_);
3005 trace_kmem_cache_free(_RET_IP_, x);
3006}
3007EXPORT_SYMBOL(kmem_cache_free);
3008
3009struct detached_freelist {
3010 struct page *page;
3011 void *tail;
3012 void *freelist;
3013 int cnt;
3014 struct kmem_cache *s;
3015};
3016
3017/*
3018 * This function progressively scans the array with free objects (with
3019 * a limited look ahead) and extract objects belonging to the same
3020 * page. It builds a detached freelist directly within the given
3021 * page/objects. This can happen without any need for
3022 * synchronization, because the objects are owned by running process.
3023 * The freelist is build up as a single linked list in the objects.
3024 * The idea is, that this detached freelist can then be bulk
3025 * transferred to the real freelist(s), but only requiring a single
3026 * synchronization primitive. Look ahead in the array is limited due
3027 * to performance reasons.
3028 */
3029static inline
3030int build_detached_freelist(struct kmem_cache *s, size_t size,
3031 void **p, struct detached_freelist *df)
3032{
3033 size_t first_skipped_index = 0;
3034 int lookahead = 3;
3035 void *object;
3036 struct page *page;
3037
3038 /* Always re-init detached_freelist */
3039 df->page = NULL;
3040
3041 do {
3042 object = p[--size];
3043 /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */
3044 } while (!object && size);
3045
3046 if (!object)
3047 return 0;
3048
3049 page = virt_to_head_page(object);
3050 if (!s) {
3051 /* Handle kalloc'ed objects */
3052 if (unlikely(!PageSlab(page))) {
3053 BUG_ON(!PageCompound(page));
3054 kfree_hook(object);
3055 __free_pages(page, compound_order(page));
3056 p[size] = NULL; /* mark object processed */
3057 return size;
3058 }
3059 /* Derive kmem_cache from object */
3060 df->s = page->slab_cache;
3061 } else {
3062 df->s = cache_from_obj(s, object); /* Support for memcg */
3063 }
3064
3065 /* Start new detached freelist */
3066 df->page = page;
3067 set_freepointer(df->s, object, NULL);
3068 df->tail = object;
3069 df->freelist = object;
3070 p[size] = NULL; /* mark object processed */
3071 df->cnt = 1;
3072
3073 while (size) {
3074 object = p[--size];
3075 if (!object)
3076 continue; /* Skip processed objects */
3077
3078 /* df->page is always set at this point */
3079 if (df->page == virt_to_head_page(object)) {
3080 /* Opportunity build freelist */
3081 set_freepointer(df->s, object, df->freelist);
3082 df->freelist = object;
3083 df->cnt++;
3084 p[size] = NULL; /* mark object processed */
3085
3086 continue;
3087 }
3088
3089 /* Limit look ahead search */
3090 if (!--lookahead)
3091 break;
3092
3093 if (!first_skipped_index)
3094 first_skipped_index = size + 1;
3095 }
3096
3097 return first_skipped_index;
3098}
3099
3100/* Note that interrupts must be enabled when calling this function. */
3101void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
3102{
3103 if (WARN_ON(!size))
3104 return;
3105
3106 do {
3107 struct detached_freelist df;
3108
3109 size = build_detached_freelist(s, size, p, &df);
3110 if (!df.page)
3111 continue;
3112
3113 slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_);
3114 } while (likely(size));
3115}
3116EXPORT_SYMBOL(kmem_cache_free_bulk);
3117
3118/* Note that interrupts must be enabled when calling this function. */
3119int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3120 void **p)
3121{
3122 struct kmem_cache_cpu *c;
3123 int i;
3124
3125 /* memcg and kmem_cache debug support */
3126 s = slab_pre_alloc_hook(s, flags);
3127 if (unlikely(!s))
3128 return false;
3129 /*
3130 * Drain objects in the per cpu slab, while disabling local
3131 * IRQs, which protects against PREEMPT and interrupts
3132 * handlers invoking normal fastpath.
3133 */
3134 local_irq_disable();
3135 c = this_cpu_ptr(s->cpu_slab);
3136
3137 for (i = 0; i < size; i++) {
3138 void *object = c->freelist;
3139
3140 if (unlikely(!object)) {
3141 /*
3142 * Invoking slow path likely have side-effect
3143 * of re-populating per CPU c->freelist
3144 */
3145 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
3146 _RET_IP_, c);
3147 if (unlikely(!p[i]))
3148 goto error;
3149
3150 c = this_cpu_ptr(s->cpu_slab);
3151 continue; /* goto for-loop */
3152 }
3153 c->freelist = get_freepointer(s, object);
3154 p[i] = object;
3155 }
3156 c->tid = next_tid(c->tid);
3157 local_irq_enable();
3158
3159 /* Clear memory outside IRQ disabled fastpath loop */
3160 if (unlikely(flags & __GFP_ZERO)) {
3161 int j;
3162
3163 for (j = 0; j < i; j++)
3164 memset(p[j], 0, s->object_size);
3165 }
3166
3167 /* memcg and kmem_cache debug support */
3168 slab_post_alloc_hook(s, flags, size, p);
3169 return i;
3170error:
3171 local_irq_enable();
3172 slab_post_alloc_hook(s, flags, i, p);
3173 __kmem_cache_free_bulk(s, i, p);
3174 return 0;
3175}
3176EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3177
3178
3179/*
3180 * Object placement in a slab is made very easy because we always start at
3181 * offset 0. If we tune the size of the object to the alignment then we can
3182 * get the required alignment by putting one properly sized object after
3183 * another.
3184 *
3185 * Notice that the allocation order determines the sizes of the per cpu
3186 * caches. Each processor has always one slab available for allocations.
3187 * Increasing the allocation order reduces the number of times that slabs
3188 * must be moved on and off the partial lists and is therefore a factor in
3189 * locking overhead.
3190 */
3191
3192/*
3193 * Mininum / Maximum order of slab pages. This influences locking overhead
3194 * and slab fragmentation. A higher order reduces the number of partial slabs
3195 * and increases the number of allocations possible without having to
3196 * take the list_lock.
3197 */
3198static unsigned int slub_min_order;
3199static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
3200static unsigned int slub_min_objects;
3201
3202/*
3203 * Calculate the order of allocation given an slab object size.
3204 *
3205 * The order of allocation has significant impact on performance and other
3206 * system components. Generally order 0 allocations should be preferred since
3207 * order 0 does not cause fragmentation in the page allocator. Larger objects
3208 * be problematic to put into order 0 slabs because there may be too much
3209 * unused space left. We go to a higher order if more than 1/16th of the slab
3210 * would be wasted.
3211 *
3212 * In order to reach satisfactory performance we must ensure that a minimum
3213 * number of objects is in one slab. Otherwise we may generate too much
3214 * activity on the partial lists which requires taking the list_lock. This is
3215 * less a concern for large slabs though which are rarely used.
3216 *
3217 * slub_max_order specifies the order where we begin to stop considering the
3218 * number of objects in a slab as critical. If we reach slub_max_order then
3219 * we try to keep the page order as low as possible. So we accept more waste
3220 * of space in favor of a small page order.
3221 *
3222 * Higher order allocations also allow the placement of more objects in a
3223 * slab and thereby reduce object handling overhead. If the user has
3224 * requested a higher mininum order then we start with that one instead of
3225 * the smallest order which will fit the object.
3226 */
3227static inline unsigned int slab_order(unsigned int size,
3228 unsigned int min_objects, unsigned int max_order,
3229 unsigned int fract_leftover, unsigned int reserved)
3230{
3231 unsigned int min_order = slub_min_order;
3232 unsigned int order;
3233
3234 if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
3235 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
3236
3237 for (order = max(min_order, (unsigned int)get_order(min_objects * size + reserved));
3238 order <= max_order; order++) {
3239
3240 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
3241 unsigned int rem;
3242
3243 rem = (slab_size - reserved) % size;
3244
3245 if (rem <= slab_size / fract_leftover)
3246 break;
3247 }
3248
3249 return order;
3250}
3251
3252static inline int calculate_order(unsigned int size, unsigned int reserved)
3253{
3254 unsigned int order;
3255 unsigned int min_objects;
3256 unsigned int max_objects;
3257
3258 /*
3259 * Attempt to find best configuration for a slab. This
3260 * works by first attempting to generate a layout with
3261 * the best configuration and backing off gradually.
3262 *
3263 * First we increase the acceptable waste in a slab. Then
3264 * we reduce the minimum objects required in a slab.
3265 */
3266 min_objects = slub_min_objects;
3267 if (!min_objects)
3268 min_objects = 4 * (fls(nr_cpu_ids) + 1);
3269 max_objects = order_objects(slub_max_order, size, reserved);
3270 min_objects = min(min_objects, max_objects);
3271
3272 while (min_objects > 1) {
3273 unsigned int fraction;
3274
3275 fraction = 16;
3276 while (fraction >= 4) {
3277 order = slab_order(size, min_objects,
3278 slub_max_order, fraction, reserved);
3279 if (order <= slub_max_order)
3280 return order;
3281 fraction /= 2;
3282 }
3283 min_objects--;
3284 }
3285
3286 /*
3287 * We were unable to place multiple objects in a slab. Now
3288 * lets see if we can place a single object there.
3289 */
3290 order = slab_order(size, 1, slub_max_order, 1, reserved);
3291 if (order <= slub_max_order)
3292 return order;
3293
3294 /*
3295 * Doh this slab cannot be placed using slub_max_order.
3296 */
3297 order = slab_order(size, 1, MAX_ORDER, 1, reserved);
3298 if (order < MAX_ORDER)
3299 return order;
3300 return -ENOSYS;
3301}
3302
3303static void
3304init_kmem_cache_node(struct kmem_cache_node *n)
3305{
3306 n->nr_partial = 0;
3307 spin_lock_init(&n->list_lock);
3308 INIT_LIST_HEAD(&n->partial);
3309#ifdef CONFIG_SLUB_DEBUG
3310 atomic_long_set(&n->nr_slabs, 0);
3311 atomic_long_set(&n->total_objects, 0);
3312 INIT_LIST_HEAD(&n->full);
3313#endif
3314}
3315
3316static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
3317{
3318 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
3319 KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
3320
3321 /*
3322 * Must align to double word boundary for the double cmpxchg
3323 * instructions to work; see __pcpu_double_call_return_bool().
3324 */
3325 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
3326 2 * sizeof(void *));
3327
3328 if (!s->cpu_slab)
3329 return 0;
3330
3331 init_kmem_cache_cpus(s);
3332
3333 return 1;
3334}
3335
3336static struct kmem_cache *kmem_cache_node;
3337
3338/*
3339 * No kmalloc_node yet so do it by hand. We know that this is the first
3340 * slab on the node for this slabcache. There are no concurrent accesses
3341 * possible.
3342 *
3343 * Note that this function only works on the kmem_cache_node
3344 * when allocating for the kmem_cache_node. This is used for bootstrapping
3345 * memory on a fresh node that has no slab structures yet.
3346 */
3347static void early_kmem_cache_node_alloc(int node)
3348{
3349 struct page *page;
3350 struct kmem_cache_node *n;
3351
3352 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
3353
3354 page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
3355
3356 BUG_ON(!page);
3357 if (page_to_nid(page) != node) {
3358 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
3359 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
3360 }
3361
3362 n = page->freelist;
3363 BUG_ON(!n);
3364 page->freelist = get_freepointer(kmem_cache_node, n);
3365 page->inuse = 1;
3366 page->frozen = 0;
3367 kmem_cache_node->node[node] = n;
3368#ifdef CONFIG_SLUB_DEBUG
3369 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
3370 init_tracking(kmem_cache_node, n);
3371#endif
3372 kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node),
3373 GFP_KERNEL);
3374 init_kmem_cache_node(n);
3375 inc_slabs_node(kmem_cache_node, node, page->objects);
3376
3377 /*
3378 * No locks need to be taken here as it has just been
3379 * initialized and there is no concurrent access.
3380 */
3381 __add_partial(n, page, DEACTIVATE_TO_HEAD);
3382}
3383
3384static void free_kmem_cache_nodes(struct kmem_cache *s)
3385{
3386 int node;
3387 struct kmem_cache_node *n;
3388
3389 for_each_kmem_cache_node(s, node, n) {
3390 s->node[node] = NULL;
3391 kmem_cache_free(kmem_cache_node, n);
3392 }
3393}
3394
3395void __kmem_cache_release(struct kmem_cache *s)
3396{
3397 cache_random_seq_destroy(s);
3398 free_percpu(s->cpu_slab);
3399 free_kmem_cache_nodes(s);
3400}
3401
3402static int init_kmem_cache_nodes(struct kmem_cache *s)
3403{
3404 int node;
3405
3406 for_each_node_state(node, N_NORMAL_MEMORY) {
3407 struct kmem_cache_node *n;
3408
3409 if (slab_state == DOWN) {
3410 early_kmem_cache_node_alloc(node);
3411 continue;
3412 }
3413 n = kmem_cache_alloc_node(kmem_cache_node,
3414 GFP_KERNEL, node);
3415
3416 if (!n) {
3417 free_kmem_cache_nodes(s);
3418 return 0;
3419 }
3420
3421 init_kmem_cache_node(n);
3422 s->node[node] = n;
3423 }
3424 return 1;
3425}
3426
3427static void set_min_partial(struct kmem_cache *s, unsigned long min)
3428{
3429 if (min < MIN_PARTIAL)
3430 min = MIN_PARTIAL;
3431 else if (min > MAX_PARTIAL)
3432 min = MAX_PARTIAL;
3433 s->min_partial = min;
3434}
3435
3436static void set_cpu_partial(struct kmem_cache *s)
3437{
3438#ifdef CONFIG_SLUB_CPU_PARTIAL
3439 /*
3440 * cpu_partial determined the maximum number of objects kept in the
3441 * per cpu partial lists of a processor.
3442 *
3443 * Per cpu partial lists mainly contain slabs that just have one
3444 * object freed. If they are used for allocation then they can be
3445 * filled up again with minimal effort. The slab will never hit the
3446 * per node partial lists and therefore no locking will be required.
3447 *
3448 * This setting also determines
3449 *
3450 * A) The number of objects from per cpu partial slabs dumped to the
3451 * per node list when we reach the limit.
3452 * B) The number of objects in cpu partial slabs to extract from the
3453 * per node list when we run out of per cpu objects. We only fetch
3454 * 50% to keep some capacity around for frees.
3455 */
3456 if (!kmem_cache_has_cpu_partial(s))
3457 s->cpu_partial = 0;
3458 else if (s->size >= PAGE_SIZE)
3459 s->cpu_partial = 2;
3460 else if (s->size >= 1024)
3461 s->cpu_partial = 6;
3462 else if (s->size >= 256)
3463 s->cpu_partial = 13;
3464 else
3465 s->cpu_partial = 30;
3466#endif
3467}
3468
3469/*
3470 * calculate_sizes() determines the order and the distribution of data within
3471 * a slab object.
3472 */
3473static int calculate_sizes(struct kmem_cache *s, int forced_order)
3474{
3475 slab_flags_t flags = s->flags;
3476 unsigned int size = s->object_size;
3477 unsigned int order;
3478
3479 /*
3480 * Round up object size to the next word boundary. We can only
3481 * place the free pointer at word boundaries and this determines
3482 * the possible location of the free pointer.
3483 */
3484 size = ALIGN(size, sizeof(void *));
3485
3486#ifdef CONFIG_SLUB_DEBUG
3487 /*
3488 * Determine if we can poison the object itself. If the user of
3489 * the slab may touch the object after free or before allocation
3490 * then we should never poison the object itself.
3491 */
3492 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
3493 !s->ctor)
3494 s->flags |= __OBJECT_POISON;
3495 else
3496 s->flags &= ~__OBJECT_POISON;
3497
3498
3499 /*
3500 * If we are Redzoning then check if there is some space between the
3501 * end of the object and the free pointer. If not then add an
3502 * additional word to have some bytes to store Redzone information.
3503 */
3504 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
3505 size += sizeof(void *);
3506#endif
3507
3508 /*
3509 * With that we have determined the number of bytes in actual use
3510 * by the object. This is the potential offset to the free pointer.
3511 */
3512 s->inuse = size;
3513
3514 if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
3515 s->ctor)) {
3516 /*
3517 * Relocate free pointer after the object if it is not
3518 * permitted to overwrite the first word of the object on
3519 * kmem_cache_free.
3520 *
3521 * This is the case if we do RCU, have a constructor or
3522 * destructor or are poisoning the objects.
3523 */
3524 s->offset = size;
3525 size += sizeof(void *);
3526 }
3527
3528#ifdef CONFIG_SLUB_DEBUG
3529 if (flags & SLAB_STORE_USER)
3530 /*
3531 * Need to store information about allocs and frees after
3532 * the object.
3533 */
3534 size += 2 * sizeof(struct track);
3535#endif
3536
3537 kasan_cache_create(s, &size, &s->flags);
3538#ifdef CONFIG_SLUB_DEBUG
3539 if (flags & SLAB_RED_ZONE) {
3540 /*
3541 * Add some empty padding so that we can catch
3542 * overwrites from earlier objects rather than let
3543 * tracking information or the free pointer be
3544 * corrupted if a user writes before the start
3545 * of the object.
3546 */
3547 size += sizeof(void *);
3548
3549 s->red_left_pad = sizeof(void *);
3550 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
3551 size += s->red_left_pad;
3552 }
3553#endif
3554
3555 /*
3556 * SLUB stores one object immediately after another beginning from
3557 * offset 0. In order to align the objects we have to simply size
3558 * each object to conform to the alignment.
3559 */
3560 size = ALIGN(size, s->align);
3561 s->size = size;
3562 if (forced_order >= 0)
3563 order = forced_order;
3564 else
3565 order = calculate_order(size, s->reserved);
3566
3567 if ((int)order < 0)
3568 return 0;
3569
3570 s->allocflags = 0;
3571 if (order)
3572 s->allocflags |= __GFP_COMP;
3573
3574 if (s->flags & SLAB_CACHE_DMA)
3575 s->allocflags |= GFP_DMA;
3576
3577 if (s->flags & SLAB_RECLAIM_ACCOUNT)
3578 s->allocflags |= __GFP_RECLAIMABLE;
3579
3580 /*
3581 * Determine the number of objects per slab
3582 */
3583 s->oo = oo_make(order, size, s->reserved);
3584 s->min = oo_make(get_order(size), size, s->reserved);
3585 if (oo_objects(s->oo) > oo_objects(s->max))
3586 s->max = s->oo;
3587
3588 return !!oo_objects(s->oo);
3589}
3590
3591static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
3592{
3593 s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor);
3594 s->reserved = 0;
3595#ifdef CONFIG_SLAB_FREELIST_HARDENED
3596 s->random = get_random_long();
3597#endif
3598
3599 if (need_reserve_slab_rcu && (s->flags & SLAB_TYPESAFE_BY_RCU))
3600 s->reserved = sizeof(struct rcu_head);
3601
3602 if (!calculate_sizes(s, -1))
3603 goto error;
3604 if (disable_higher_order_debug) {
3605 /*
3606 * Disable debugging flags that store metadata if the min slab
3607 * order increased.
3608 */
3609 if (get_order(s->size) > get_order(s->object_size)) {
3610 s->flags &= ~DEBUG_METADATA_FLAGS;
3611 s->offset = 0;
3612 if (!calculate_sizes(s, -1))
3613 goto error;
3614 }
3615 }
3616
3617#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3618 defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3619 if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
3620 /* Enable fast mode */
3621 s->flags |= __CMPXCHG_DOUBLE;
3622#endif
3623
3624 /*
3625 * The larger the object size is, the more pages we want on the partial
3626 * list to avoid pounding the page allocator excessively.
3627 */
3628 set_min_partial(s, ilog2(s->size) / 2);
3629
3630 set_cpu_partial(s);
3631
3632#ifdef CONFIG_NUMA
3633 s->remote_node_defrag_ratio = 1000;
3634#endif
3635
3636 /* Initialize the pre-computed randomized freelist if slab is up */
3637 if (slab_state >= UP) {
3638 if (init_cache_random_seq(s))
3639 goto error;
3640 }
3641
3642 if (!init_kmem_cache_nodes(s))
3643 goto error;
3644
3645 if (alloc_kmem_cache_cpus(s))
3646 return 0;
3647
3648 free_kmem_cache_nodes(s);
3649error:
3650 if (flags & SLAB_PANIC)
3651 panic("Cannot create slab %s size=%u realsize=%u order=%u offset=%u flags=%lx\n",
3652 s->name, s->size, s->size,
3653 oo_order(s->oo), s->offset, (unsigned long)flags);
3654 return -EINVAL;
3655}
3656
3657static void list_slab_objects(struct kmem_cache *s, struct page *page,
3658 const char *text)
3659{
3660#ifdef CONFIG_SLUB_DEBUG
3661 void *addr = page_address(page);
3662 void *p;
3663 unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3664 sizeof(long), GFP_ATOMIC);
3665 if (!map)
3666 return;
3667 slab_err(s, page, text, s->name);
3668 slab_lock(page);
3669
3670 get_map(s, page, map);
3671 for_each_object(p, s, addr, page->objects) {
3672
3673 if (!test_bit(slab_index(p, s, addr), map)) {
3674 pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr);
3675 print_tracking(s, p);
3676 }
3677 }
3678 slab_unlock(page);
3679 kfree(map);
3680#endif
3681}
3682
3683/*
3684 * Attempt to free all partial slabs on a node.
3685 * This is called from __kmem_cache_shutdown(). We must take list_lock
3686 * because sysfs file might still access partial list after the shutdowning.
3687 */
3688static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3689{
3690 LIST_HEAD(discard);
3691 struct page *page, *h;
3692
3693 BUG_ON(irqs_disabled());
3694 spin_lock_irq(&n->list_lock);
3695 list_for_each_entry_safe(page, h, &n->partial, lru) {
3696 if (!page->inuse) {
3697 remove_partial(n, page);
3698 list_add(&page->lru, &discard);
3699 } else {
3700 list_slab_objects(s, page,
3701 "Objects remaining in %s on __kmem_cache_shutdown()");
3702 }
3703 }
3704 spin_unlock_irq(&n->list_lock);
3705
3706 list_for_each_entry_safe(page, h, &discard, lru)
3707 discard_slab(s, page);
3708}
3709
3710bool __kmem_cache_empty(struct kmem_cache *s)
3711{
3712 int node;
3713 struct kmem_cache_node *n;
3714
3715 for_each_kmem_cache_node(s, node, n)
3716 if (n->nr_partial || slabs_node(s, node))
3717 return false;
3718 return true;
3719}
3720
3721/*
3722 * Release all resources used by a slab cache.
3723 */
3724int __kmem_cache_shutdown(struct kmem_cache *s)
3725{
3726 int node;
3727 struct kmem_cache_node *n;
3728
3729 flush_all(s);
3730 /* Attempt to free all objects */
3731 for_each_kmem_cache_node(s, node, n) {
3732 free_partial(s, n);
3733 if (n->nr_partial || slabs_node(s, node))
3734 return 1;
3735 }
3736 sysfs_slab_remove(s);
3737 return 0;
3738}
3739
3740/********************************************************************
3741 * Kmalloc subsystem
3742 *******************************************************************/
3743
3744static int __init setup_slub_min_order(char *str)
3745{
3746 get_option(&str, (int *)&slub_min_order);
3747
3748 return 1;
3749}
3750
3751__setup("slub_min_order=", setup_slub_min_order);
3752
3753static int __init setup_slub_max_order(char *str)
3754{
3755 get_option(&str, (int *)&slub_max_order);
3756 slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
3757
3758 return 1;
3759}
3760
3761__setup("slub_max_order=", setup_slub_max_order);
3762
3763static int __init setup_slub_min_objects(char *str)
3764{
3765 get_option(&str, (int *)&slub_min_objects);
3766
3767 return 1;
3768}
3769
3770__setup("slub_min_objects=", setup_slub_min_objects);
3771
3772void *__kmalloc(size_t size, gfp_t flags)
3773{
3774 struct kmem_cache *s;
3775 void *ret;
3776
3777 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3778 return kmalloc_large(size, flags);
3779
3780 s = kmalloc_slab(size, flags);
3781
3782 if (unlikely(ZERO_OR_NULL_PTR(s)))
3783 return s;
3784
3785 ret = slab_alloc(s, flags, _RET_IP_);
3786
3787 trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3788
3789 kasan_kmalloc(s, ret, size, flags);
3790
3791 return ret;
3792}
3793EXPORT_SYMBOL(__kmalloc);
3794
3795#ifdef CONFIG_NUMA
3796static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3797{
3798 struct page *page;
3799 void *ptr = NULL;
3800
3801 flags |= __GFP_COMP;
3802 page = alloc_pages_node(node, flags, get_order(size));
3803 if (page)
3804 ptr = page_address(page);
3805
3806 kmalloc_large_node_hook(ptr, size, flags);
3807 return ptr;
3808}
3809
3810void *__kmalloc_node(size_t size, gfp_t flags, int node)
3811{
3812 struct kmem_cache *s;
3813 void *ret;
3814
3815 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3816 ret = kmalloc_large_node(size, flags, node);
3817
3818 trace_kmalloc_node(_RET_IP_, ret,
3819 size, PAGE_SIZE << get_order(size),
3820 flags, node);
3821
3822 return ret;
3823 }
3824
3825 s = kmalloc_slab(size, flags);
3826
3827 if (unlikely(ZERO_OR_NULL_PTR(s)))
3828 return s;
3829
3830 ret = slab_alloc_node(s, flags, node, _RET_IP_);
3831
3832 trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3833
3834 kasan_kmalloc(s, ret, size, flags);
3835
3836 return ret;
3837}
3838EXPORT_SYMBOL(__kmalloc_node);
3839#endif
3840
3841#ifdef CONFIG_HARDENED_USERCOPY
3842/*
3843 * Rejects incorrectly sized objects and objects that are to be copied
3844 * to/from userspace but do not fall entirely within the containing slab
3845 * cache's usercopy region.
3846 *
3847 * Returns NULL if check passes, otherwise const char * to name of cache
3848 * to indicate an error.
3849 */
3850void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
3851 bool to_user)
3852{
3853 struct kmem_cache *s;
3854 unsigned int offset;
3855 size_t object_size;
3856
3857 /* Find object and usable object size. */
3858 s = page->slab_cache;
3859
3860 /* Reject impossible pointers. */
3861 if (ptr < page_address(page))
3862 usercopy_abort("SLUB object not in SLUB page?!", NULL,
3863 to_user, 0, n);
3864
3865 /* Find offset within object. */
3866 offset = (ptr - page_address(page)) % s->size;
3867
3868 /* Adjust for redzone and reject if within the redzone. */
3869 if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) {
3870 if (offset < s->red_left_pad)
3871 usercopy_abort("SLUB object in left red zone",
3872 s->name, to_user, offset, n);
3873 offset -= s->red_left_pad;
3874 }
3875
3876 /* Allow address range falling entirely within usercopy region. */
3877 if (offset >= s->useroffset &&
3878 offset - s->useroffset <= s->usersize &&
3879 n <= s->useroffset - offset + s->usersize)
3880 return;
3881
3882 /*
3883 * If the copy is still within the allocated object, produce
3884 * a warning instead of rejecting the copy. This is intended
3885 * to be a temporary method to find any missing usercopy
3886 * whitelists.
3887 */
3888 object_size = slab_ksize(s);
3889 if (usercopy_fallback &&
3890 offset <= object_size && n <= object_size - offset) {
3891 usercopy_warn("SLUB object", s->name, to_user, offset, n);
3892 return;
3893 }
3894
3895 usercopy_abort("SLUB object", s->name, to_user, offset, n);
3896}
3897#endif /* CONFIG_HARDENED_USERCOPY */
3898
3899static size_t __ksize(const void *object)
3900{
3901 struct page *page;
3902
3903 if (unlikely(object == ZERO_SIZE_PTR))
3904 return 0;
3905
3906 page = virt_to_head_page(object);
3907
3908 if (unlikely(!PageSlab(page))) {
3909 WARN_ON(!PageCompound(page));
3910 return PAGE_SIZE << compound_order(page);
3911 }
3912
3913 return slab_ksize(page->slab_cache);
3914}
3915
3916size_t ksize(const void *object)
3917{
3918 size_t size = __ksize(object);
3919 /* We assume that ksize callers could use whole allocated area,
3920 * so we need to unpoison this area.
3921 */
3922 kasan_unpoison_shadow(object, size);
3923 return size;
3924}
3925EXPORT_SYMBOL(ksize);
3926
3927void kfree(const void *x)
3928{
3929 struct page *page;
3930 void *object = (void *)x;
3931
3932 trace_kfree(_RET_IP_, x);
3933
3934 if (unlikely(ZERO_OR_NULL_PTR(x)))
3935 return;
3936
3937 page = virt_to_head_page(x);
3938 if (unlikely(!PageSlab(page))) {
3939 BUG_ON(!PageCompound(page));
3940 kfree_hook(object);
3941 __free_pages(page, compound_order(page));
3942 return;
3943 }
3944 slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_);
3945}
3946EXPORT_SYMBOL(kfree);
3947
3948#define SHRINK_PROMOTE_MAX 32
3949
3950/*
3951 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
3952 * up most to the head of the partial lists. New allocations will then
3953 * fill those up and thus they can be removed from the partial lists.
3954 *
3955 * The slabs with the least items are placed last. This results in them
3956 * being allocated from last increasing the chance that the last objects
3957 * are freed in them.
3958 */
3959int __kmem_cache_shrink(struct kmem_cache *s)
3960{
3961 int node;
3962 int i;
3963 struct kmem_cache_node *n;
3964 struct page *page;
3965 struct page *t;
3966 struct list_head discard;
3967 struct list_head promote[SHRINK_PROMOTE_MAX];
3968 unsigned long flags;
3969 int ret = 0;
3970
3971 flush_all(s);
3972 for_each_kmem_cache_node(s, node, n) {
3973 INIT_LIST_HEAD(&discard);
3974 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
3975 INIT_LIST_HEAD(promote + i);
3976
3977 spin_lock_irqsave(&n->list_lock, flags);
3978
3979 /*
3980 * Build lists of slabs to discard or promote.
3981 *
3982 * Note that concurrent frees may occur while we hold the
3983 * list_lock. page->inuse here is the upper limit.
3984 */
3985 list_for_each_entry_safe(page, t, &n->partial, lru) {
3986 int free = page->objects - page->inuse;
3987
3988 /* Do not reread page->inuse */
3989 barrier();
3990
3991 /* We do not keep full slabs on the list */
3992 BUG_ON(free <= 0);
3993
3994 if (free == page->objects) {
3995 list_move(&page->lru, &discard);
3996 n->nr_partial--;
3997 } else if (free <= SHRINK_PROMOTE_MAX)
3998 list_move(&page->lru, promote + free - 1);
3999 }
4000
4001 /*
4002 * Promote the slabs filled up most to the head of the
4003 * partial list.
4004 */
4005 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
4006 list_splice(promote + i, &n->partial);
4007
4008 spin_unlock_irqrestore(&n->list_lock, flags);
4009
4010 /* Release empty slabs */
4011 list_for_each_entry_safe(page, t, &discard, lru)
4012 discard_slab(s, page);
4013
4014 if (slabs_node(s, node))
4015 ret = 1;
4016 }
4017
4018 return ret;
4019}
4020
4021#ifdef CONFIG_MEMCG
4022static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s)
4023{
4024 /*
4025 * Called with all the locks held after a sched RCU grace period.
4026 * Even if @s becomes empty after shrinking, we can't know that @s
4027 * doesn't have allocations already in-flight and thus can't
4028 * destroy @s until the associated memcg is released.
4029 *
4030 * However, let's remove the sysfs files for empty caches here.
4031 * Each cache has a lot of interface files which aren't
4032 * particularly useful for empty draining caches; otherwise, we can
4033 * easily end up with millions of unnecessary sysfs files on
4034 * systems which have a lot of memory and transient cgroups.
4035 */
4036 if (!__kmem_cache_shrink(s))
4037 sysfs_slab_remove(s);
4038}
4039
4040void __kmemcg_cache_deactivate(struct kmem_cache *s)
4041{
4042 /*
4043 * Disable empty slabs caching. Used to avoid pinning offline
4044 * memory cgroups by kmem pages that can be freed.
4045 */
4046 slub_set_cpu_partial(s, 0);
4047 s->min_partial = 0;
4048
4049 /*
4050 * s->cpu_partial is checked locklessly (see put_cpu_partial), so
4051 * we have to make sure the change is visible before shrinking.
4052 */
4053 slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu);
4054}
4055#endif
4056
4057static int slab_mem_going_offline_callback(void *arg)
4058{
4059 struct kmem_cache *s;
4060
4061 mutex_lock(&slab_mutex);
4062 list_for_each_entry(s, &slab_caches, list)
4063 __kmem_cache_shrink(s);
4064 mutex_unlock(&slab_mutex);
4065
4066 return 0;
4067}
4068
4069static void slab_mem_offline_callback(void *arg)
4070{
4071 struct kmem_cache_node *n;
4072 struct kmem_cache *s;
4073 struct memory_notify *marg = arg;
4074 int offline_node;
4075
4076 offline_node = marg->status_change_nid_normal;
4077
4078 /*
4079 * If the node still has available memory. we need kmem_cache_node
4080 * for it yet.
4081 */
4082 if (offline_node < 0)
4083 return;
4084
4085 mutex_lock(&slab_mutex);
4086 list_for_each_entry(s, &slab_caches, list) {
4087 n = get_node(s, offline_node);
4088 if (n) {
4089 /*
4090 * if n->nr_slabs > 0, slabs still exist on the node
4091 * that is going down. We were unable to free them,
4092 * and offline_pages() function shouldn't call this
4093 * callback. So, we must fail.
4094 */
4095 BUG_ON(slabs_node(s, offline_node));
4096
4097 s->node[offline_node] = NULL;
4098 kmem_cache_free(kmem_cache_node, n);
4099 }
4100 }
4101 mutex_unlock(&slab_mutex);
4102}
4103
4104static int slab_mem_going_online_callback(void *arg)
4105{
4106 struct kmem_cache_node *n;
4107 struct kmem_cache *s;
4108 struct memory_notify *marg = arg;
4109 int nid = marg->status_change_nid_normal;
4110 int ret = 0;
4111
4112 /*
4113 * If the node's memory is already available, then kmem_cache_node is
4114 * already created. Nothing to do.
4115 */
4116 if (nid < 0)
4117 return 0;
4118
4119 /*
4120 * We are bringing a node online. No memory is available yet. We must
4121 * allocate a kmem_cache_node structure in order to bring the node
4122 * online.
4123 */
4124 mutex_lock(&slab_mutex);
4125 list_for_each_entry(s, &slab_caches, list) {
4126 /*
4127 * XXX: kmem_cache_alloc_node will fallback to other nodes
4128 * since memory is not yet available from the node that
4129 * is brought up.
4130 */
4131 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
4132 if (!n) {
4133 ret = -ENOMEM;
4134 goto out;
4135 }
4136 init_kmem_cache_node(n);
4137 s->node[nid] = n;
4138 }
4139out:
4140 mutex_unlock(&slab_mutex);
4141 return ret;
4142}
4143
4144static int slab_memory_callback(struct notifier_block *self,
4145 unsigned long action, void *arg)
4146{
4147 int ret = 0;
4148
4149 switch (action) {
4150 case MEM_GOING_ONLINE:
4151 ret = slab_mem_going_online_callback(arg);
4152 break;
4153 case MEM_GOING_OFFLINE:
4154 ret = slab_mem_going_offline_callback(arg);
4155 break;
4156 case MEM_OFFLINE:
4157 case MEM_CANCEL_ONLINE:
4158 slab_mem_offline_callback(arg);
4159 break;
4160 case MEM_ONLINE:
4161 case MEM_CANCEL_OFFLINE:
4162 break;
4163 }
4164 if (ret)
4165 ret = notifier_from_errno(ret);
4166 else
4167 ret = NOTIFY_OK;
4168 return ret;
4169}
4170
4171static struct notifier_block slab_memory_callback_nb = {
4172 .notifier_call = slab_memory_callback,
4173 .priority = SLAB_CALLBACK_PRI,
4174};
4175
4176/********************************************************************
4177 * Basic setup of slabs
4178 *******************************************************************/
4179
4180/*
4181 * Used for early kmem_cache structures that were allocated using
4182 * the page allocator. Allocate them properly then fix up the pointers
4183 * that may be pointing to the wrong kmem_cache structure.
4184 */
4185
4186static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
4187{
4188 int node;
4189 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
4190 struct kmem_cache_node *n;
4191
4192 memcpy(s, static_cache, kmem_cache->object_size);
4193
4194 /*
4195 * This runs very early, and only the boot processor is supposed to be
4196 * up. Even if it weren't true, IRQs are not up so we couldn't fire
4197 * IPIs around.
4198 */
4199 __flush_cpu_slab(s, smp_processor_id());
4200 for_each_kmem_cache_node(s, node, n) {
4201 struct page *p;
4202
4203 list_for_each_entry(p, &n->partial, lru)
4204 p->slab_cache = s;
4205
4206#ifdef CONFIG_SLUB_DEBUG
4207 list_for_each_entry(p, &n->full, lru)
4208 p->slab_cache = s;
4209#endif
4210 }
4211 slab_init_memcg_params(s);
4212 list_add(&s->list, &slab_caches);
4213 memcg_link_cache(s);
4214 return s;
4215}
4216
4217void __init kmem_cache_init(void)
4218{
4219 static __initdata struct kmem_cache boot_kmem_cache,
4220 boot_kmem_cache_node;
4221
4222 if (debug_guardpage_minorder())
4223 slub_max_order = 0;
4224
4225 kmem_cache_node = &boot_kmem_cache_node;
4226 kmem_cache = &boot_kmem_cache;
4227
4228 create_boot_cache(kmem_cache_node, "kmem_cache_node",
4229 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
4230
4231 register_hotmemory_notifier(&slab_memory_callback_nb);
4232
4233 /* Able to allocate the per node structures */
4234 slab_state = PARTIAL;
4235
4236 create_boot_cache(kmem_cache, "kmem_cache",
4237 offsetof(struct kmem_cache, node) +
4238 nr_node_ids * sizeof(struct kmem_cache_node *),
4239 SLAB_HWCACHE_ALIGN, 0, 0);
4240
4241 kmem_cache = bootstrap(&boot_kmem_cache);
4242
4243 /*
4244 * Allocate kmem_cache_node properly from the kmem_cache slab.
4245 * kmem_cache_node is separately allocated so no need to
4246 * update any list pointers.
4247 */
4248 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
4249
4250 /* Now we can use the kmem_cache to allocate kmalloc slabs */
4251 setup_kmalloc_cache_index_table();
4252 create_kmalloc_caches(0);
4253
4254 /* Setup random freelists for each cache */
4255 init_freelist_randomization();
4256
4257 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
4258 slub_cpu_dead);
4259
4260 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%d\n",
4261 cache_line_size(),
4262 slub_min_order, slub_max_order, slub_min_objects,
4263 nr_cpu_ids, nr_node_ids);
4264}
4265
4266void __init kmem_cache_init_late(void)
4267{
4268}
4269
4270struct kmem_cache *
4271__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
4272 slab_flags_t flags, void (*ctor)(void *))
4273{
4274 struct kmem_cache *s, *c;
4275
4276 s = find_mergeable(size, align, flags, name, ctor);
4277 if (s) {
4278 s->refcount++;
4279
4280 /*
4281 * Adjust the object sizes so that we clear
4282 * the complete object on kzalloc.
4283 */
4284 s->object_size = max(s->object_size, size);
4285 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
4286
4287 for_each_memcg_cache(c, s) {
4288 c->object_size = s->object_size;
4289 c->inuse = max(c->inuse, ALIGN(size, sizeof(void *)));
4290 }
4291
4292 if (sysfs_slab_alias(s, name)) {
4293 s->refcount--;
4294 s = NULL;
4295 }
4296 }
4297
4298 return s;
4299}
4300
4301int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
4302{
4303 int err;
4304
4305 err = kmem_cache_open(s, flags);
4306 if (err)
4307 return err;
4308
4309 /* Mutex is not taken during early boot */
4310 if (slab_state <= UP)
4311 return 0;
4312
4313 memcg_propagate_slab_attrs(s);
4314 err = sysfs_slab_add(s);
4315 if (err)
4316 __kmem_cache_release(s);
4317
4318 return err;
4319}
4320
4321void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4322{
4323 struct kmem_cache *s;
4324 void *ret;
4325
4326 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
4327 return kmalloc_large(size, gfpflags);
4328
4329 s = kmalloc_slab(size, gfpflags);
4330
4331 if (unlikely(ZERO_OR_NULL_PTR(s)))
4332 return s;
4333
4334 ret = slab_alloc(s, gfpflags, caller);
4335
4336 /* Honor the call site pointer we received. */
4337 trace_kmalloc(caller, ret, size, s->size, gfpflags);
4338
4339 return ret;
4340}
4341
4342#ifdef CONFIG_NUMA
4343void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4344 int node, unsigned long caller)
4345{
4346 struct kmem_cache *s;
4347 void *ret;
4348
4349 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
4350 ret = kmalloc_large_node(size, gfpflags, node);
4351
4352 trace_kmalloc_node(caller, ret,
4353 size, PAGE_SIZE << get_order(size),
4354 gfpflags, node);
4355
4356 return ret;
4357 }
4358
4359 s = kmalloc_slab(size, gfpflags);
4360
4361 if (unlikely(ZERO_OR_NULL_PTR(s)))
4362 return s;
4363
4364 ret = slab_alloc_node(s, gfpflags, node, caller);
4365
4366 /* Honor the call site pointer we received. */
4367 trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4368
4369 return ret;
4370}
4371#endif
4372
4373#ifdef CONFIG_SYSFS
4374static int count_inuse(struct page *page)
4375{
4376 return page->inuse;
4377}
4378
4379static int count_total(struct page *page)
4380{
4381 return page->objects;
4382}
4383#endif
4384
4385#ifdef CONFIG_SLUB_DEBUG
4386static int validate_slab(struct kmem_cache *s, struct page *page,
4387 unsigned long *map)
4388{
4389 void *p;
4390 void *addr = page_address(page);
4391
4392 if (!check_slab(s, page) ||
4393 !on_freelist(s, page, NULL))
4394 return 0;
4395
4396 /* Now we know that a valid freelist exists */
4397 bitmap_zero(map, page->objects);
4398
4399 get_map(s, page, map);
4400 for_each_object(p, s, addr, page->objects) {
4401 if (test_bit(slab_index(p, s, addr), map))
4402 if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4403 return 0;
4404 }
4405
4406 for_each_object(p, s, addr, page->objects)
4407 if (!test_bit(slab_index(p, s, addr), map))
4408 if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4409 return 0;
4410 return 1;
4411}
4412
4413static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4414 unsigned long *map)
4415{
4416 slab_lock(page);
4417 validate_slab(s, page, map);
4418 slab_unlock(page);
4419}
4420
4421static int validate_slab_node(struct kmem_cache *s,
4422 struct kmem_cache_node *n, unsigned long *map)
4423{
4424 unsigned long count = 0;
4425 struct page *page;
4426 unsigned long flags;
4427
4428 spin_lock_irqsave(&n->list_lock, flags);
4429
4430 list_for_each_entry(page, &n->partial, lru) {
4431 validate_slab_slab(s, page, map);
4432 count++;
4433 }
4434 if (count != n->nr_partial)
4435 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
4436 s->name, count, n->nr_partial);
4437
4438 if (!(s->flags & SLAB_STORE_USER))
4439 goto out;
4440
4441 list_for_each_entry(page, &n->full, lru) {
4442 validate_slab_slab(s, page, map);
4443 count++;
4444 }
4445 if (count != atomic_long_read(&n->nr_slabs))
4446 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
4447 s->name, count, atomic_long_read(&n->nr_slabs));
4448
4449out:
4450 spin_unlock_irqrestore(&n->list_lock, flags);
4451 return count;
4452}
4453
4454static long validate_slab_cache(struct kmem_cache *s)
4455{
4456 int node;
4457 unsigned long count = 0;
4458 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4459 sizeof(unsigned long), GFP_KERNEL);
4460 struct kmem_cache_node *n;
4461
4462 if (!map)
4463 return -ENOMEM;
4464
4465 flush_all(s);
4466 for_each_kmem_cache_node(s, node, n)
4467 count += validate_slab_node(s, n, map);
4468 kfree(map);
4469 return count;
4470}
4471/*
4472 * Generate lists of code addresses where slabcache objects are allocated
4473 * and freed.
4474 */
4475
4476struct location {
4477 unsigned long count;
4478 unsigned long addr;
4479 long long sum_time;
4480 long min_time;
4481 long max_time;
4482 long min_pid;
4483 long max_pid;
4484 DECLARE_BITMAP(cpus, NR_CPUS);
4485 nodemask_t nodes;
4486};
4487
4488struct loc_track {
4489 unsigned long max;
4490 unsigned long count;
4491 struct location *loc;
4492};
4493
4494static void free_loc_track(struct loc_track *t)
4495{
4496 if (t->max)
4497 free_pages((unsigned long)t->loc,
4498 get_order(sizeof(struct location) * t->max));
4499}
4500
4501static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4502{
4503 struct location *l;
4504 int order;
4505
4506 order = get_order(sizeof(struct location) * max);
4507
4508 l = (void *)__get_free_pages(flags, order);
4509 if (!l)
4510 return 0;
4511
4512 if (t->count) {
4513 memcpy(l, t->loc, sizeof(struct location) * t->count);
4514 free_loc_track(t);
4515 }
4516 t->max = max;
4517 t->loc = l;
4518 return 1;
4519}
4520
4521static int add_location(struct loc_track *t, struct kmem_cache *s,
4522 const struct track *track)
4523{
4524 long start, end, pos;
4525 struct location *l;
4526 unsigned long caddr;
4527 unsigned long age = jiffies - track->when;
4528
4529 start = -1;
4530 end = t->count;
4531
4532 for ( ; ; ) {
4533 pos = start + (end - start + 1) / 2;
4534
4535 /*
4536 * There is nothing at "end". If we end up there
4537 * we need to add something to before end.
4538 */
4539 if (pos == end)
4540 break;
4541
4542 caddr = t->loc[pos].addr;
4543 if (track->addr == caddr) {
4544
4545 l = &t->loc[pos];
4546 l->count++;
4547 if (track->when) {
4548 l->sum_time += age;
4549 if (age < l->min_time)
4550 l->min_time = age;
4551 if (age > l->max_time)
4552 l->max_time = age;
4553
4554 if (track->pid < l->min_pid)
4555 l->min_pid = track->pid;
4556 if (track->pid > l->max_pid)
4557 l->max_pid = track->pid;
4558
4559 cpumask_set_cpu(track->cpu,
4560 to_cpumask(l->cpus));
4561 }
4562 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4563 return 1;
4564 }
4565
4566 if (track->addr < caddr)
4567 end = pos;
4568 else
4569 start = pos;
4570 }
4571
4572 /*
4573 * Not found. Insert new tracking element.
4574 */
4575 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4576 return 0;
4577
4578 l = t->loc + pos;
4579 if (pos < t->count)
4580 memmove(l + 1, l,
4581 (t->count - pos) * sizeof(struct location));
4582 t->count++;
4583 l->count = 1;
4584 l->addr = track->addr;
4585 l->sum_time = age;
4586 l->min_time = age;
4587 l->max_time = age;
4588 l->min_pid = track->pid;
4589 l->max_pid = track->pid;
4590 cpumask_clear(to_cpumask(l->cpus));
4591 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4592 nodes_clear(l->nodes);
4593 node_set(page_to_nid(virt_to_page(track)), l->nodes);
4594 return 1;
4595}
4596
4597static void process_slab(struct loc_track *t, struct kmem_cache *s,
4598 struct page *page, enum track_item alloc,
4599 unsigned long *map)
4600{
4601 void *addr = page_address(page);
4602 void *p;
4603
4604 bitmap_zero(map, page->objects);
4605 get_map(s, page, map);
4606
4607 for_each_object(p, s, addr, page->objects)
4608 if (!test_bit(slab_index(p, s, addr), map))
4609 add_location(t, s, get_track(s, p, alloc));
4610}
4611
4612static int list_locations(struct kmem_cache *s, char *buf,
4613 enum track_item alloc)
4614{
4615 int len = 0;
4616 unsigned long i;
4617 struct loc_track t = { 0, 0, NULL };
4618 int node;
4619 unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4620 sizeof(unsigned long), GFP_KERNEL);
4621 struct kmem_cache_node *n;
4622
4623 if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4624 GFP_KERNEL)) {
4625 kfree(map);
4626 return sprintf(buf, "Out of memory\n");
4627 }
4628 /* Push back cpu slabs */
4629 flush_all(s);
4630
4631 for_each_kmem_cache_node(s, node, n) {
4632 unsigned long flags;
4633 struct page *page;
4634
4635 if (!atomic_long_read(&n->nr_slabs))
4636 continue;
4637
4638 spin_lock_irqsave(&n->list_lock, flags);
4639 list_for_each_entry(page, &n->partial, lru)
4640 process_slab(&t, s, page, alloc, map);
4641 list_for_each_entry(page, &n->full, lru)
4642 process_slab(&t, s, page, alloc, map);
4643 spin_unlock_irqrestore(&n->list_lock, flags);
4644 }
4645
4646 for (i = 0; i < t.count; i++) {
4647 struct location *l = &t.loc[i];
4648
4649 if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4650 break;
4651 len += sprintf(buf + len, "%7ld ", l->count);
4652
4653 if (l->addr)
4654 len += sprintf(buf + len, "%pS", (void *)l->addr);
4655 else
4656 len += sprintf(buf + len, "<not-available>");
4657
4658 if (l->sum_time != l->min_time) {
4659 len += sprintf(buf + len, " age=%ld/%ld/%ld",
4660 l->min_time,
4661 (long)div_u64(l->sum_time, l->count),
4662 l->max_time);
4663 } else
4664 len += sprintf(buf + len, " age=%ld",
4665 l->min_time);
4666
4667 if (l->min_pid != l->max_pid)
4668 len += sprintf(buf + len, " pid=%ld-%ld",
4669 l->min_pid, l->max_pid);
4670 else
4671 len += sprintf(buf + len, " pid=%ld",
4672 l->min_pid);
4673
4674 if (num_online_cpus() > 1 &&
4675 !cpumask_empty(to_cpumask(l->cpus)) &&
4676 len < PAGE_SIZE - 60)
4677 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4678 " cpus=%*pbl",
4679 cpumask_pr_args(to_cpumask(l->cpus)));
4680
4681 if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4682 len < PAGE_SIZE - 60)
4683 len += scnprintf(buf + len, PAGE_SIZE - len - 50,
4684 " nodes=%*pbl",
4685 nodemask_pr_args(&l->nodes));
4686
4687 len += sprintf(buf + len, "\n");
4688 }
4689
4690 free_loc_track(&t);
4691 kfree(map);
4692 if (!t.count)
4693 len += sprintf(buf, "No data\n");
4694 return len;
4695}
4696#endif
4697
4698#ifdef SLUB_RESILIENCY_TEST
4699static void __init resiliency_test(void)
4700{
4701 u8 *p;
4702
4703 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10);
4704
4705 pr_err("SLUB resiliency testing\n");
4706 pr_err("-----------------------\n");
4707 pr_err("A. Corruption after allocation\n");
4708
4709 p = kzalloc(16, GFP_KERNEL);
4710 p[16] = 0x12;
4711 pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n",
4712 p + 16);
4713
4714 validate_slab_cache(kmalloc_caches[4]);
4715
4716 /* Hmmm... The next two are dangerous */
4717 p = kzalloc(32, GFP_KERNEL);
4718 p[32 + sizeof(void *)] = 0x34;
4719 pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n",
4720 p);
4721 pr_err("If allocated object is overwritten then not detectable\n\n");
4722
4723 validate_slab_cache(kmalloc_caches[5]);
4724 p = kzalloc(64, GFP_KERNEL);
4725 p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4726 *p = 0x56;
4727 pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4728 p);
4729 pr_err("If allocated object is overwritten then not detectable\n\n");
4730 validate_slab_cache(kmalloc_caches[6]);
4731
4732 pr_err("\nB. Corruption after free\n");
4733 p = kzalloc(128, GFP_KERNEL);
4734 kfree(p);
4735 *p = 0x78;
4736 pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4737 validate_slab_cache(kmalloc_caches[7]);
4738
4739 p = kzalloc(256, GFP_KERNEL);
4740 kfree(p);
4741 p[50] = 0x9a;
4742 pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p);
4743 validate_slab_cache(kmalloc_caches[8]);
4744
4745 p = kzalloc(512, GFP_KERNEL);
4746 kfree(p);
4747 p[512] = 0xab;
4748 pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4749 validate_slab_cache(kmalloc_caches[9]);
4750}
4751#else
4752#ifdef CONFIG_SYSFS
4753static void resiliency_test(void) {};
4754#endif
4755#endif
4756
4757#ifdef CONFIG_SYSFS
4758enum slab_stat_type {
4759 SL_ALL, /* All slabs */
4760 SL_PARTIAL, /* Only partially allocated slabs */
4761 SL_CPU, /* Only slabs used for cpu caches */
4762 SL_OBJECTS, /* Determine allocated objects not slabs */
4763 SL_TOTAL /* Determine object capacity not slabs */
4764};
4765
4766#define SO_ALL (1 << SL_ALL)
4767#define SO_PARTIAL (1 << SL_PARTIAL)
4768#define SO_CPU (1 << SL_CPU)
4769#define SO_OBJECTS (1 << SL_OBJECTS)
4770#define SO_TOTAL (1 << SL_TOTAL)
4771
4772#ifdef CONFIG_MEMCG
4773static bool memcg_sysfs_enabled = IS_ENABLED(CONFIG_SLUB_MEMCG_SYSFS_ON);
4774
4775static int __init setup_slub_memcg_sysfs(char *str)
4776{
4777 int v;
4778
4779 if (get_option(&str, &v) > 0)
4780 memcg_sysfs_enabled = v;
4781
4782 return 1;
4783}
4784
4785__setup("slub_memcg_sysfs=", setup_slub_memcg_sysfs);
4786#endif
4787
4788static ssize_t show_slab_objects(struct kmem_cache *s,
4789 char *buf, unsigned long flags)
4790{
4791 unsigned long total = 0;
4792 int node;
4793 int x;
4794 unsigned long *nodes;
4795
4796 nodes = kzalloc(sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4797 if (!nodes)
4798 return -ENOMEM;
4799
4800 if (flags & SO_CPU) {
4801 int cpu;
4802
4803 for_each_possible_cpu(cpu) {
4804 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
4805 cpu);
4806 int node;
4807 struct page *page;
4808
4809 page = READ_ONCE(c->page);
4810 if (!page)
4811 continue;
4812
4813 node = page_to_nid(page);
4814 if (flags & SO_TOTAL)
4815 x = page->objects;
4816 else if (flags & SO_OBJECTS)
4817 x = page->inuse;
4818 else
4819 x = 1;
4820
4821 total += x;
4822 nodes[node] += x;
4823
4824 page = slub_percpu_partial_read_once(c);
4825 if (page) {
4826 node = page_to_nid(page);
4827 if (flags & SO_TOTAL)
4828 WARN_ON_ONCE(1);
4829 else if (flags & SO_OBJECTS)
4830 WARN_ON_ONCE(1);
4831 else
4832 x = page->pages;
4833 total += x;
4834 nodes[node] += x;
4835 }
4836 }
4837 }
4838
4839 get_online_mems();
4840#ifdef CONFIG_SLUB_DEBUG
4841 if (flags & SO_ALL) {
4842 struct kmem_cache_node *n;
4843
4844 for_each_kmem_cache_node(s, node, n) {
4845
4846 if (flags & SO_TOTAL)
4847 x = atomic_long_read(&n->total_objects);
4848 else if (flags & SO_OBJECTS)
4849 x = atomic_long_read(&n->total_objects) -
4850 count_partial(n, count_free);
4851 else
4852 x = atomic_long_read(&n->nr_slabs);
4853 total += x;
4854 nodes[node] += x;
4855 }
4856
4857 } else
4858#endif
4859 if (flags & SO_PARTIAL) {
4860 struct kmem_cache_node *n;
4861
4862 for_each_kmem_cache_node(s, node, n) {
4863 if (flags & SO_TOTAL)
4864 x = count_partial(n, count_total);
4865 else if (flags & SO_OBJECTS)
4866 x = count_partial(n, count_inuse);
4867 else
4868 x = n->nr_partial;
4869 total += x;
4870 nodes[node] += x;
4871 }
4872 }
4873 x = sprintf(buf, "%lu", total);
4874#ifdef CONFIG_NUMA
4875 for (node = 0; node < nr_node_ids; node++)
4876 if (nodes[node])
4877 x += sprintf(buf + x, " N%d=%lu",
4878 node, nodes[node]);
4879#endif
4880 put_online_mems();
4881 kfree(nodes);
4882 return x + sprintf(buf + x, "\n");
4883}
4884
4885#ifdef CONFIG_SLUB_DEBUG
4886static int any_slab_objects(struct kmem_cache *s)
4887{
4888 int node;
4889 struct kmem_cache_node *n;
4890
4891 for_each_kmem_cache_node(s, node, n)
4892 if (atomic_long_read(&n->total_objects))
4893 return 1;
4894
4895 return 0;
4896}
4897#endif
4898
4899#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4900#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4901
4902struct slab_attribute {
4903 struct attribute attr;
4904 ssize_t (*show)(struct kmem_cache *s, char *buf);
4905 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4906};
4907
4908#define SLAB_ATTR_RO(_name) \
4909 static struct slab_attribute _name##_attr = \
4910 __ATTR(_name, 0400, _name##_show, NULL)
4911
4912#define SLAB_ATTR(_name) \
4913 static struct slab_attribute _name##_attr = \
4914 __ATTR(_name, 0600, _name##_show, _name##_store)
4915
4916static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4917{
4918 return sprintf(buf, "%u\n", s->size);
4919}
4920SLAB_ATTR_RO(slab_size);
4921
4922static ssize_t align_show(struct kmem_cache *s, char *buf)
4923{
4924 return sprintf(buf, "%u\n", s->align);
4925}
4926SLAB_ATTR_RO(align);
4927
4928static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4929{
4930 return sprintf(buf, "%u\n", s->object_size);
4931}
4932SLAB_ATTR_RO(object_size);
4933
4934static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4935{
4936 return sprintf(buf, "%u\n", oo_objects(s->oo));
4937}
4938SLAB_ATTR_RO(objs_per_slab);
4939
4940static ssize_t order_store(struct kmem_cache *s,
4941 const char *buf, size_t length)
4942{
4943 unsigned int order;
4944 int err;
4945
4946 err = kstrtouint(buf, 10, &order);
4947 if (err)
4948 return err;
4949
4950 if (order > slub_max_order || order < slub_min_order)
4951 return -EINVAL;
4952
4953 calculate_sizes(s, order);
4954 return length;
4955}
4956
4957static ssize_t order_show(struct kmem_cache *s, char *buf)
4958{
4959 return sprintf(buf, "%u\n", oo_order(s->oo));
4960}
4961SLAB_ATTR(order);
4962
4963static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4964{
4965 return sprintf(buf, "%lu\n", s->min_partial);
4966}
4967
4968static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4969 size_t length)
4970{
4971 unsigned long min;
4972 int err;
4973
4974 err = kstrtoul(buf, 10, &min);
4975 if (err)
4976 return err;
4977
4978 set_min_partial(s, min);
4979 return length;
4980}
4981SLAB_ATTR(min_partial);
4982
4983static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4984{
4985 return sprintf(buf, "%u\n", slub_cpu_partial(s));
4986}
4987
4988static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4989 size_t length)
4990{
4991 unsigned int objects;
4992 int err;
4993
4994 err = kstrtouint(buf, 10, &objects);
4995 if (err)
4996 return err;
4997 if (objects && !kmem_cache_has_cpu_partial(s))
4998 return -EINVAL;
4999
5000 slub_set_cpu_partial(s, objects);
5001 flush_all(s);
5002 return length;
5003}
5004SLAB_ATTR(cpu_partial);
5005
5006static ssize_t ctor_show(struct kmem_cache *s, char *buf)
5007{
5008 if (!s->ctor)
5009 return 0;
5010 return sprintf(buf, "%pS\n", s->ctor);
5011}
5012SLAB_ATTR_RO(ctor);
5013
5014static ssize_t aliases_show(struct kmem_cache *s, char *buf)
5015{
5016 return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
5017}
5018SLAB_ATTR_RO(aliases);
5019
5020static ssize_t partial_show(struct kmem_cache *s, char *buf)
5021{
5022 return show_slab_objects(s, buf, SO_PARTIAL);
5023}
5024SLAB_ATTR_RO(partial);
5025
5026static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
5027{
5028 return show_slab_objects(s, buf, SO_CPU);
5029}
5030SLAB_ATTR_RO(cpu_slabs);
5031
5032static ssize_t objects_show(struct kmem_cache *s, char *buf)
5033{
5034 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
5035}
5036SLAB_ATTR_RO(objects);
5037
5038static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
5039{
5040 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
5041}
5042SLAB_ATTR_RO(objects_partial);
5043
5044static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
5045{
5046 int objects = 0;
5047 int pages = 0;
5048 int cpu;
5049 int len;
5050
5051 for_each_online_cpu(cpu) {
5052 struct page *page;
5053
5054 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5055
5056 if (page) {
5057 pages += page->pages;
5058 objects += page->pobjects;
5059 }
5060 }
5061
5062 len = sprintf(buf, "%d(%d)", objects, pages);
5063
5064#ifdef CONFIG_SMP
5065 for_each_online_cpu(cpu) {
5066 struct page *page;
5067
5068 page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
5069
5070 if (page && len < PAGE_SIZE - 20)
5071 len += sprintf(buf + len, " C%d=%d(%d)", cpu,
5072 page->pobjects, page->pages);
5073 }
5074#endif
5075 return len + sprintf(buf + len, "\n");
5076}
5077SLAB_ATTR_RO(slabs_cpu_partial);
5078
5079static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
5080{
5081 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
5082}
5083
5084static ssize_t reclaim_account_store(struct kmem_cache *s,
5085 const char *buf, size_t length)
5086{
5087 s->flags &= ~SLAB_RECLAIM_ACCOUNT;
5088 if (buf[0] == '1')
5089 s->flags |= SLAB_RECLAIM_ACCOUNT;
5090 return length;
5091}
5092SLAB_ATTR(reclaim_account);
5093
5094static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
5095{
5096 return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
5097}
5098SLAB_ATTR_RO(hwcache_align);
5099
5100#ifdef CONFIG_ZONE_DMA
5101static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
5102{
5103 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
5104}
5105SLAB_ATTR_RO(cache_dma);
5106#endif
5107
5108static ssize_t usersize_show(struct kmem_cache *s, char *buf)
5109{
5110 return sprintf(buf, "%u\n", s->usersize);
5111}
5112SLAB_ATTR_RO(usersize);
5113
5114static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
5115{
5116 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
5117}
5118SLAB_ATTR_RO(destroy_by_rcu);
5119
5120static ssize_t reserved_show(struct kmem_cache *s, char *buf)
5121{
5122 return sprintf(buf, "%u\n", s->reserved);
5123}
5124SLAB_ATTR_RO(reserved);
5125
5126#ifdef CONFIG_SLUB_DEBUG
5127static ssize_t slabs_show(struct kmem_cache *s, char *buf)
5128{
5129 return show_slab_objects(s, buf, SO_ALL);
5130}
5131SLAB_ATTR_RO(slabs);
5132
5133static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
5134{
5135 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
5136}
5137SLAB_ATTR_RO(total_objects);
5138
5139static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
5140{
5141 return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
5142}
5143
5144static ssize_t sanity_checks_store(struct kmem_cache *s,
5145 const char *buf, size_t length)
5146{
5147 s->flags &= ~SLAB_CONSISTENCY_CHECKS;
5148 if (buf[0] == '1') {
5149 s->flags &= ~__CMPXCHG_DOUBLE;
5150 s->flags |= SLAB_CONSISTENCY_CHECKS;
5151 }
5152 return length;
5153}
5154SLAB_ATTR(sanity_checks);
5155
5156static ssize_t trace_show(struct kmem_cache *s, char *buf)
5157{
5158 return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
5159}
5160
5161static ssize_t trace_store(struct kmem_cache *s, const char *buf,
5162 size_t length)
5163{
5164 /*
5165 * Tracing a merged cache is going to give confusing results
5166 * as well as cause other issues like converting a mergeable
5167 * cache into an umergeable one.
5168 */
5169 if (s->refcount > 1)
5170 return -EINVAL;
5171
5172 s->flags &= ~SLAB_TRACE;
5173 if (buf[0] == '1') {
5174 s->flags &= ~__CMPXCHG_DOUBLE;
5175 s->flags |= SLAB_TRACE;
5176 }
5177 return length;
5178}
5179SLAB_ATTR(trace);
5180
5181static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
5182{
5183 return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
5184}
5185
5186static ssize_t red_zone_store(struct kmem_cache *s,
5187 const char *buf, size_t length)
5188{
5189 if (any_slab_objects(s))
5190 return -EBUSY;
5191
5192 s->flags &= ~SLAB_RED_ZONE;
5193 if (buf[0] == '1') {
5194 s->flags |= SLAB_RED_ZONE;
5195 }
5196 calculate_sizes(s, -1);
5197 return length;
5198}
5199SLAB_ATTR(red_zone);
5200
5201static ssize_t poison_show(struct kmem_cache *s, char *buf)
5202{
5203 return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
5204}
5205
5206static ssize_t poison_store(struct kmem_cache *s,
5207 const char *buf, size_t length)
5208{
5209 if (any_slab_objects(s))
5210 return -EBUSY;
5211
5212 s->flags &= ~SLAB_POISON;
5213 if (buf[0] == '1') {
5214 s->flags |= SLAB_POISON;
5215 }
5216 calculate_sizes(s, -1);
5217 return length;
5218}
5219SLAB_ATTR(poison);
5220
5221static ssize_t store_user_show(struct kmem_cache *s, char *buf)
5222{
5223 return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
5224}
5225
5226static ssize_t store_user_store(struct kmem_cache *s,
5227 const char *buf, size_t length)
5228{
5229 if (any_slab_objects(s))
5230 return -EBUSY;
5231
5232 s->flags &= ~SLAB_STORE_USER;
5233 if (buf[0] == '1') {
5234 s->flags &= ~__CMPXCHG_DOUBLE;
5235 s->flags |= SLAB_STORE_USER;
5236 }
5237 calculate_sizes(s, -1);
5238 return length;
5239}
5240SLAB_ATTR(store_user);
5241
5242static ssize_t validate_show(struct kmem_cache *s, char *buf)
5243{
5244 return 0;
5245}
5246
5247static ssize_t validate_store(struct kmem_cache *s,
5248 const char *buf, size_t length)
5249{
5250 int ret = -EINVAL;
5251
5252 if (buf[0] == '1') {
5253 ret = validate_slab_cache(s);
5254 if (ret >= 0)
5255 ret = length;
5256 }
5257 return ret;
5258}
5259SLAB_ATTR(validate);
5260
5261static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
5262{
5263 if (!(s->flags & SLAB_STORE_USER))
5264 return -ENOSYS;
5265 return list_locations(s, buf, TRACK_ALLOC);
5266}
5267SLAB_ATTR_RO(alloc_calls);
5268
5269static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
5270{
5271 if (!(s->flags & SLAB_STORE_USER))
5272 return -ENOSYS;
5273 return list_locations(s, buf, TRACK_FREE);
5274}
5275SLAB_ATTR_RO(free_calls);
5276#endif /* CONFIG_SLUB_DEBUG */
5277
5278#ifdef CONFIG_FAILSLAB
5279static ssize_t failslab_show(struct kmem_cache *s, char *buf)
5280{
5281 return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
5282}
5283
5284static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
5285 size_t length)
5286{
5287 if (s->refcount > 1)
5288 return -EINVAL;
5289
5290 s->flags &= ~SLAB_FAILSLAB;
5291 if (buf[0] == '1')
5292 s->flags |= SLAB_FAILSLAB;
5293 return length;
5294}
5295SLAB_ATTR(failslab);
5296#endif
5297
5298static ssize_t shrink_show(struct kmem_cache *s, char *buf)
5299{
5300 return 0;
5301}
5302
5303static ssize_t shrink_store(struct kmem_cache *s,
5304 const char *buf, size_t length)
5305{
5306 if (buf[0] == '1')
5307 kmem_cache_shrink(s);
5308 else
5309 return -EINVAL;
5310 return length;
5311}
5312SLAB_ATTR(shrink);
5313
5314#ifdef CONFIG_NUMA
5315static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
5316{
5317 return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10);
5318}
5319
5320static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5321 const char *buf, size_t length)
5322{
5323 unsigned int ratio;
5324 int err;
5325
5326 err = kstrtouint(buf, 10, &ratio);
5327 if (err)
5328 return err;
5329 if (ratio > 100)
5330 return -ERANGE;
5331
5332 s->remote_node_defrag_ratio = ratio * 10;
5333
5334 return length;
5335}
5336SLAB_ATTR(remote_node_defrag_ratio);
5337#endif
5338
5339#ifdef CONFIG_SLUB_STATS
5340static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5341{
5342 unsigned long sum = 0;
5343 int cpu;
5344 int len;
5345 int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5346
5347 if (!data)
5348 return -ENOMEM;
5349
5350 for_each_online_cpu(cpu) {
5351 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5352
5353 data[cpu] = x;
5354 sum += x;
5355 }
5356
5357 len = sprintf(buf, "%lu", sum);
5358
5359#ifdef CONFIG_SMP
5360 for_each_online_cpu(cpu) {
5361 if (data[cpu] && len < PAGE_SIZE - 20)
5362 len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
5363 }
5364#endif
5365 kfree(data);
5366 return len + sprintf(buf + len, "\n");
5367}
5368
5369static void clear_stat(struct kmem_cache *s, enum stat_item si)
5370{
5371 int cpu;
5372
5373 for_each_online_cpu(cpu)
5374 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5375}
5376
5377#define STAT_ATTR(si, text) \
5378static ssize_t text##_show(struct kmem_cache *s, char *buf) \
5379{ \
5380 return show_stat(s, buf, si); \
5381} \
5382static ssize_t text##_store(struct kmem_cache *s, \
5383 const char *buf, size_t length) \
5384{ \
5385 if (buf[0] != '0') \
5386 return -EINVAL; \
5387 clear_stat(s, si); \
5388 return length; \
5389} \
5390SLAB_ATTR(text); \
5391
5392STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5393STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5394STAT_ATTR(FREE_FASTPATH, free_fastpath);
5395STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5396STAT_ATTR(FREE_FROZEN, free_frozen);
5397STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5398STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5399STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5400STAT_ATTR(ALLOC_SLAB, alloc_slab);
5401STAT_ATTR(ALLOC_REFILL, alloc_refill);
5402STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5403STAT_ATTR(FREE_SLAB, free_slab);
5404STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5405STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5406STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5407STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5408STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5409STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5410STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5411STAT_ATTR(ORDER_FALLBACK, order_fallback);
5412STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5413STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5414STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5415STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5416STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5417STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
5418#endif
5419
5420static struct attribute *slab_attrs[] = {
5421 &slab_size_attr.attr,
5422 &object_size_attr.attr,
5423 &objs_per_slab_attr.attr,
5424 &order_attr.attr,
5425 &min_partial_attr.attr,
5426 &cpu_partial_attr.attr,
5427 &objects_attr.attr,
5428 &objects_partial_attr.attr,
5429 &partial_attr.attr,
5430 &cpu_slabs_attr.attr,
5431 &ctor_attr.attr,
5432 &aliases_attr.attr,
5433 &align_attr.attr,
5434 &hwcache_align_attr.attr,
5435 &reclaim_account_attr.attr,
5436 &destroy_by_rcu_attr.attr,
5437 &shrink_attr.attr,
5438 &reserved_attr.attr,
5439 &slabs_cpu_partial_attr.attr,
5440#ifdef CONFIG_SLUB_DEBUG
5441 &total_objects_attr.attr,
5442 &slabs_attr.attr,
5443 &sanity_checks_attr.attr,
5444 &trace_attr.attr,
5445 &red_zone_attr.attr,
5446 &poison_attr.attr,
5447 &store_user_attr.attr,
5448 &validate_attr.attr,
5449 &alloc_calls_attr.attr,
5450 &free_calls_attr.attr,
5451#endif
5452#ifdef CONFIG_ZONE_DMA
5453 &cache_dma_attr.attr,
5454#endif
5455#ifdef CONFIG_NUMA
5456 &remote_node_defrag_ratio_attr.attr,
5457#endif
5458#ifdef CONFIG_SLUB_STATS
5459 &alloc_fastpath_attr.attr,
5460 &alloc_slowpath_attr.attr,
5461 &free_fastpath_attr.attr,
5462 &free_slowpath_attr.attr,
5463 &free_frozen_attr.attr,
5464 &free_add_partial_attr.attr,
5465 &free_remove_partial_attr.attr,
5466 &alloc_from_partial_attr.attr,
5467 &alloc_slab_attr.attr,
5468 &alloc_refill_attr.attr,
5469 &alloc_node_mismatch_attr.attr,
5470 &free_slab_attr.attr,
5471 &cpuslab_flush_attr.attr,
5472 &deactivate_full_attr.attr,
5473 &deactivate_empty_attr.attr,
5474 &deactivate_to_head_attr.attr,
5475 &deactivate_to_tail_attr.attr,
5476 &deactivate_remote_frees_attr.attr,
5477 &deactivate_bypass_attr.attr,
5478 &order_fallback_attr.attr,
5479 &cmpxchg_double_fail_attr.attr,
5480 &cmpxchg_double_cpu_fail_attr.attr,
5481 &cpu_partial_alloc_attr.attr,
5482 &cpu_partial_free_attr.attr,
5483 &cpu_partial_node_attr.attr,
5484 &cpu_partial_drain_attr.attr,
5485#endif
5486#ifdef CONFIG_FAILSLAB
5487 &failslab_attr.attr,
5488#endif
5489 &usersize_attr.attr,
5490
5491 NULL
5492};
5493
5494static const struct attribute_group slab_attr_group = {
5495 .attrs = slab_attrs,
5496};
5497
5498static ssize_t slab_attr_show(struct kobject *kobj,
5499 struct attribute *attr,
5500 char *buf)
5501{
5502 struct slab_attribute *attribute;
5503 struct kmem_cache *s;
5504 int err;
5505
5506 attribute = to_slab_attr(attr);
5507 s = to_slab(kobj);
5508
5509 if (!attribute->show)
5510 return -EIO;
5511
5512 err = attribute->show(s, buf);
5513
5514 return err;
5515}
5516
5517static ssize_t slab_attr_store(struct kobject *kobj,
5518 struct attribute *attr,
5519 const char *buf, size_t len)
5520{
5521 struct slab_attribute *attribute;
5522 struct kmem_cache *s;
5523 int err;
5524
5525 attribute = to_slab_attr(attr);
5526 s = to_slab(kobj);
5527
5528 if (!attribute->store)
5529 return -EIO;
5530
5531 err = attribute->store(s, buf, len);
5532#ifdef CONFIG_MEMCG
5533 if (slab_state >= FULL && err >= 0 && is_root_cache(s)) {
5534 struct kmem_cache *c;
5535
5536 mutex_lock(&slab_mutex);
5537 if (s->max_attr_size < len)
5538 s->max_attr_size = len;
5539
5540 /*
5541 * This is a best effort propagation, so this function's return
5542 * value will be determined by the parent cache only. This is
5543 * basically because not all attributes will have a well
5544 * defined semantics for rollbacks - most of the actions will
5545 * have permanent effects.
5546 *
5547 * Returning the error value of any of the children that fail
5548 * is not 100 % defined, in the sense that users seeing the
5549 * error code won't be able to know anything about the state of
5550 * the cache.
5551 *
5552 * Only returning the error code for the parent cache at least
5553 * has well defined semantics. The cache being written to
5554 * directly either failed or succeeded, in which case we loop
5555 * through the descendants with best-effort propagation.
5556 */
5557 for_each_memcg_cache(c, s)
5558 attribute->store(c, buf, len);
5559 mutex_unlock(&slab_mutex);
5560 }
5561#endif
5562 return err;
5563}
5564
5565static void memcg_propagate_slab_attrs(struct kmem_cache *s)
5566{
5567#ifdef CONFIG_MEMCG
5568 int i;
5569 char *buffer = NULL;
5570 struct kmem_cache *root_cache;
5571
5572 if (is_root_cache(s))
5573 return;
5574
5575 root_cache = s->memcg_params.root_cache;
5576
5577 /*
5578 * This mean this cache had no attribute written. Therefore, no point
5579 * in copying default values around
5580 */
5581 if (!root_cache->max_attr_size)
5582 return;
5583
5584 for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) {
5585 char mbuf[64];
5586 char *buf;
5587 struct slab_attribute *attr = to_slab_attr(slab_attrs[i]);
5588 ssize_t len;
5589
5590 if (!attr || !attr->store || !attr->show)
5591 continue;
5592
5593 /*
5594 * It is really bad that we have to allocate here, so we will
5595 * do it only as a fallback. If we actually allocate, though,
5596 * we can just use the allocated buffer until the end.
5597 *
5598 * Most of the slub attributes will tend to be very small in
5599 * size, but sysfs allows buffers up to a page, so they can
5600 * theoretically happen.
5601 */
5602 if (buffer)
5603 buf = buffer;
5604 else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf))
5605 buf = mbuf;
5606 else {
5607 buffer = (char *) get_zeroed_page(GFP_KERNEL);
5608 if (WARN_ON(!buffer))
5609 continue;
5610 buf = buffer;
5611 }
5612
5613 len = attr->show(root_cache, buf);
5614 if (len > 0)
5615 attr->store(s, buf, len);
5616 }
5617
5618 if (buffer)
5619 free_page((unsigned long)buffer);
5620#endif
5621}
5622
5623static void kmem_cache_release(struct kobject *k)
5624{
5625 slab_kmem_cache_release(to_slab(k));
5626}
5627
5628static const struct sysfs_ops slab_sysfs_ops = {
5629 .show = slab_attr_show,
5630 .store = slab_attr_store,
5631};
5632
5633static struct kobj_type slab_ktype = {
5634 .sysfs_ops = &slab_sysfs_ops,
5635 .release = kmem_cache_release,
5636};
5637
5638static int uevent_filter(struct kset *kset, struct kobject *kobj)
5639{
5640 struct kobj_type *ktype = get_ktype(kobj);
5641
5642 if (ktype == &slab_ktype)
5643 return 1;
5644 return 0;
5645}
5646
5647static const struct kset_uevent_ops slab_uevent_ops = {
5648 .filter = uevent_filter,
5649};
5650
5651static struct kset *slab_kset;
5652
5653static inline struct kset *cache_kset(struct kmem_cache *s)
5654{
5655#ifdef CONFIG_MEMCG
5656 if (!is_root_cache(s))
5657 return s->memcg_params.root_cache->memcg_kset;
5658#endif
5659 return slab_kset;
5660}
5661
5662#define ID_STR_LENGTH 64
5663
5664/* Create a unique string id for a slab cache:
5665 *
5666 * Format :[flags-]size
5667 */
5668static char *create_unique_id(struct kmem_cache *s)
5669{
5670 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5671 char *p = name;
5672
5673 BUG_ON(!name);
5674
5675 *p++ = ':';
5676 /*
5677 * First flags affecting slabcache operations. We will only
5678 * get here for aliasable slabs so we do not need to support
5679 * too many flags. The flags here must cover all flags that
5680 * are matched during merging to guarantee that the id is
5681 * unique.
5682 */
5683 if (s->flags & SLAB_CACHE_DMA)
5684 *p++ = 'd';
5685 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5686 *p++ = 'a';
5687 if (s->flags & SLAB_CONSISTENCY_CHECKS)
5688 *p++ = 'F';
5689 if (s->flags & SLAB_ACCOUNT)
5690 *p++ = 'A';
5691 if (p != name + 1)
5692 *p++ = '-';
5693 p += sprintf(p, "%07u", s->size);
5694
5695 BUG_ON(p > name + ID_STR_LENGTH - 1);
5696 return name;
5697}
5698
5699static void sysfs_slab_remove_workfn(struct work_struct *work)
5700{
5701 struct kmem_cache *s =
5702 container_of(work, struct kmem_cache, kobj_remove_work);
5703
5704 if (!s->kobj.state_in_sysfs)
5705 /*
5706 * For a memcg cache, this may be called during
5707 * deactivation and again on shutdown. Remove only once.
5708 * A cache is never shut down before deactivation is
5709 * complete, so no need to worry about synchronization.
5710 */
5711 goto out;
5712
5713#ifdef CONFIG_MEMCG
5714 kset_unregister(s->memcg_kset);
5715#endif
5716 kobject_uevent(&s->kobj, KOBJ_REMOVE);
5717 kobject_del(&s->kobj);
5718out:
5719 kobject_put(&s->kobj);
5720}
5721
5722static int sysfs_slab_add(struct kmem_cache *s)
5723{
5724 int err;
5725 const char *name;
5726 struct kset *kset = cache_kset(s);
5727 int unmergeable = slab_unmergeable(s);
5728
5729 INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn);
5730
5731 if (!kset) {
5732 kobject_init(&s->kobj, &slab_ktype);
5733 return 0;
5734 }
5735
5736 if (!unmergeable && disable_higher_order_debug &&
5737 (slub_debug & DEBUG_METADATA_FLAGS))
5738 unmergeable = 1;
5739
5740 if (unmergeable) {
5741 /*
5742 * Slabcache can never be merged so we can use the name proper.
5743 * This is typically the case for debug situations. In that
5744 * case we can catch duplicate names easily.
5745 */
5746 sysfs_remove_link(&slab_kset->kobj, s->name);
5747 name = s->name;
5748 } else {
5749 /*
5750 * Create a unique name for the slab as a target
5751 * for the symlinks.
5752 */
5753 name = create_unique_id(s);
5754 }
5755
5756 s->kobj.kset = kset;
5757 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
5758 if (err)
5759 goto out;
5760
5761 err = sysfs_create_group(&s->kobj, &slab_attr_group);
5762 if (err)
5763 goto out_del_kobj;
5764
5765#ifdef CONFIG_MEMCG
5766 if (is_root_cache(s) && memcg_sysfs_enabled) {
5767 s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj);
5768 if (!s->memcg_kset) {
5769 err = -ENOMEM;
5770 goto out_del_kobj;
5771 }
5772 }
5773#endif
5774
5775 kobject_uevent(&s->kobj, KOBJ_ADD);
5776 if (!unmergeable) {
5777 /* Setup first alias */
5778 sysfs_slab_alias(s, s->name);
5779 }
5780out:
5781 if (!unmergeable)
5782 kfree(name);
5783 return err;
5784out_del_kobj:
5785 kobject_del(&s->kobj);
5786 goto out;
5787}
5788
5789static void sysfs_slab_remove(struct kmem_cache *s)
5790{
5791 if (slab_state < FULL)
5792 /*
5793 * Sysfs has not been setup yet so no need to remove the
5794 * cache from sysfs.
5795 */
5796 return;
5797
5798 kobject_get(&s->kobj);
5799 schedule_work(&s->kobj_remove_work);
5800}
5801
5802void sysfs_slab_release(struct kmem_cache *s)
5803{
5804 if (slab_state >= FULL)
5805 kobject_put(&s->kobj);
5806}
5807
5808/*
5809 * Need to buffer aliases during bootup until sysfs becomes
5810 * available lest we lose that information.
5811 */
5812struct saved_alias {
5813 struct kmem_cache *s;
5814 const char *name;
5815 struct saved_alias *next;
5816};
5817
5818static struct saved_alias *alias_list;
5819
5820static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5821{
5822 struct saved_alias *al;
5823
5824 if (slab_state == FULL) {
5825 /*
5826 * If we have a leftover link then remove it.
5827 */
5828 sysfs_remove_link(&slab_kset->kobj, name);
5829 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5830 }
5831
5832 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5833 if (!al)
5834 return -ENOMEM;
5835
5836 al->s = s;
5837 al->name = name;
5838 al->next = alias_list;
5839 alias_list = al;
5840 return 0;
5841}
5842
5843static int __init slab_sysfs_init(void)
5844{
5845 struct kmem_cache *s;
5846 int err;
5847
5848 mutex_lock(&slab_mutex);
5849
5850 slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5851 if (!slab_kset) {
5852 mutex_unlock(&slab_mutex);
5853 pr_err("Cannot register slab subsystem.\n");
5854 return -ENOSYS;
5855 }
5856
5857 slab_state = FULL;
5858
5859 list_for_each_entry(s, &slab_caches, list) {
5860 err = sysfs_slab_add(s);
5861 if (err)
5862 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
5863 s->name);
5864 }
5865
5866 while (alias_list) {
5867 struct saved_alias *al = alias_list;
5868
5869 alias_list = alias_list->next;
5870 err = sysfs_slab_alias(al->s, al->name);
5871 if (err)
5872 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
5873 al->name);
5874 kfree(al);
5875 }
5876
5877 mutex_unlock(&slab_mutex);
5878 resiliency_test();
5879 return 0;
5880}
5881
5882__initcall(slab_sysfs_init);
5883#endif /* CONFIG_SYSFS */
5884
5885/*
5886 * The /proc/slabinfo ABI
5887 */
5888#ifdef CONFIG_SLUB_DEBUG
5889void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
5890{
5891 unsigned long nr_slabs = 0;
5892 unsigned long nr_objs = 0;
5893 unsigned long nr_free = 0;
5894 int node;
5895 struct kmem_cache_node *n;
5896
5897 for_each_kmem_cache_node(s, node, n) {
5898 nr_slabs += node_nr_slabs(n);
5899 nr_objs += node_nr_objs(n);
5900 nr_free += count_partial(n, count_free);
5901 }
5902
5903 sinfo->active_objs = nr_objs - nr_free;
5904 sinfo->num_objs = nr_objs;
5905 sinfo->active_slabs = nr_slabs;
5906 sinfo->num_slabs = nr_slabs;
5907 sinfo->objects_per_slab = oo_objects(s->oo);
5908 sinfo->cache_order = oo_order(s->oo);
5909}
5910
5911void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
5912{
5913}
5914
5915ssize_t slabinfo_write(struct file *file, const char __user *buffer,
5916 size_t count, loff_t *ppos)
5917{
5918 return -EIO;
5919}
5920#endif /* CONFIG_SLUB_DEBUG */
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * SLUB: A slab allocator that limits cache line use instead of queuing
4 * objects in per cpu and per node lists.
5 *
6 * The allocator synchronizes using per slab locks or atomic operations
7 * and only uses a centralized lock to manage a pool of partial slabs.
8 *
9 * (C) 2007 SGI, Christoph Lameter
10 * (C) 2011 Linux Foundation, Christoph Lameter
11 */
12
13#include <linux/mm.h>
14#include <linux/swap.h> /* mm_account_reclaimed_pages() */
15#include <linux/module.h>
16#include <linux/bit_spinlock.h>
17#include <linux/interrupt.h>
18#include <linux/swab.h>
19#include <linux/bitops.h>
20#include <linux/slab.h>
21#include "slab.h"
22#include <linux/proc_fs.h>
23#include <linux/seq_file.h>
24#include <linux/kasan.h>
25#include <linux/kmsan.h>
26#include <linux/cpu.h>
27#include <linux/cpuset.h>
28#include <linux/mempolicy.h>
29#include <linux/ctype.h>
30#include <linux/stackdepot.h>
31#include <linux/debugobjects.h>
32#include <linux/kallsyms.h>
33#include <linux/kfence.h>
34#include <linux/memory.h>
35#include <linux/math64.h>
36#include <linux/fault-inject.h>
37#include <linux/kmemleak.h>
38#include <linux/stacktrace.h>
39#include <linux/prefetch.h>
40#include <linux/memcontrol.h>
41#include <linux/random.h>
42#include <kunit/test.h>
43#include <kunit/test-bug.h>
44#include <linux/sort.h>
45
46#include <linux/debugfs.h>
47#include <trace/events/kmem.h>
48
49#include "internal.h"
50
51/*
52 * Lock order:
53 * 1. slab_mutex (Global Mutex)
54 * 2. node->list_lock (Spinlock)
55 * 3. kmem_cache->cpu_slab->lock (Local lock)
56 * 4. slab_lock(slab) (Only on some arches)
57 * 5. object_map_lock (Only for debugging)
58 *
59 * slab_mutex
60 *
61 * The role of the slab_mutex is to protect the list of all the slabs
62 * and to synchronize major metadata changes to slab cache structures.
63 * Also synchronizes memory hotplug callbacks.
64 *
65 * slab_lock
66 *
67 * The slab_lock is a wrapper around the page lock, thus it is a bit
68 * spinlock.
69 *
70 * The slab_lock is only used on arches that do not have the ability
71 * to do a cmpxchg_double. It only protects:
72 *
73 * A. slab->freelist -> List of free objects in a slab
74 * B. slab->inuse -> Number of objects in use
75 * C. slab->objects -> Number of objects in slab
76 * D. slab->frozen -> frozen state
77 *
78 * Frozen slabs
79 *
80 * If a slab is frozen then it is exempt from list management. It is
81 * the cpu slab which is actively allocated from by the processor that
82 * froze it and it is not on any list. The processor that froze the
83 * slab is the one who can perform list operations on the slab. Other
84 * processors may put objects onto the freelist but the processor that
85 * froze the slab is the only one that can retrieve the objects from the
86 * slab's freelist.
87 *
88 * CPU partial slabs
89 *
90 * The partially empty slabs cached on the CPU partial list are used
91 * for performance reasons, which speeds up the allocation process.
92 * These slabs are not frozen, but are also exempt from list management,
93 * by clearing the PG_workingset flag when moving out of the node
94 * partial list. Please see __slab_free() for more details.
95 *
96 * To sum up, the current scheme is:
97 * - node partial slab: PG_Workingset && !frozen
98 * - cpu partial slab: !PG_Workingset && !frozen
99 * - cpu slab: !PG_Workingset && frozen
100 * - full slab: !PG_Workingset && !frozen
101 *
102 * list_lock
103 *
104 * The list_lock protects the partial and full list on each node and
105 * the partial slab counter. If taken then no new slabs may be added or
106 * removed from the lists nor make the number of partial slabs be modified.
107 * (Note that the total number of slabs is an atomic value that may be
108 * modified without taking the list lock).
109 *
110 * The list_lock is a centralized lock and thus we avoid taking it as
111 * much as possible. As long as SLUB does not have to handle partial
112 * slabs, operations can continue without any centralized lock. F.e.
113 * allocating a long series of objects that fill up slabs does not require
114 * the list lock.
115 *
116 * For debug caches, all allocations are forced to go through a list_lock
117 * protected region to serialize against concurrent validation.
118 *
119 * cpu_slab->lock local lock
120 *
121 * This locks protect slowpath manipulation of all kmem_cache_cpu fields
122 * except the stat counters. This is a percpu structure manipulated only by
123 * the local cpu, so the lock protects against being preempted or interrupted
124 * by an irq. Fast path operations rely on lockless operations instead.
125 *
126 * On PREEMPT_RT, the local lock neither disables interrupts nor preemption
127 * which means the lockless fastpath cannot be used as it might interfere with
128 * an in-progress slow path operations. In this case the local lock is always
129 * taken but it still utilizes the freelist for the common operations.
130 *
131 * lockless fastpaths
132 *
133 * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
134 * are fully lockless when satisfied from the percpu slab (and when
135 * cmpxchg_double is possible to use, otherwise slab_lock is taken).
136 * They also don't disable preemption or migration or irqs. They rely on
137 * the transaction id (tid) field to detect being preempted or moved to
138 * another cpu.
139 *
140 * irq, preemption, migration considerations
141 *
142 * Interrupts are disabled as part of list_lock or local_lock operations, or
143 * around the slab_lock operation, in order to make the slab allocator safe
144 * to use in the context of an irq.
145 *
146 * In addition, preemption (or migration on PREEMPT_RT) is disabled in the
147 * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
148 * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
149 * doesn't have to be revalidated in each section protected by the local lock.
150 *
151 * SLUB assigns one slab for allocation to each processor.
152 * Allocations only occur from these slabs called cpu slabs.
153 *
154 * Slabs with free elements are kept on a partial list and during regular
155 * operations no list for full slabs is used. If an object in a full slab is
156 * freed then the slab will show up again on the partial lists.
157 * We track full slabs for debugging purposes though because otherwise we
158 * cannot scan all objects.
159 *
160 * Slabs are freed when they become empty. Teardown and setup is
161 * minimal so we rely on the page allocators per cpu caches for
162 * fast frees and allocs.
163 *
164 * slab->frozen The slab is frozen and exempt from list processing.
165 * This means that the slab is dedicated to a purpose
166 * such as satisfying allocations for a specific
167 * processor. Objects may be freed in the slab while
168 * it is frozen but slab_free will then skip the usual
169 * list operations. It is up to the processor holding
170 * the slab to integrate the slab into the slab lists
171 * when the slab is no longer needed.
172 *
173 * One use of this flag is to mark slabs that are
174 * used for allocations. Then such a slab becomes a cpu
175 * slab. The cpu slab may be equipped with an additional
176 * freelist that allows lockless access to
177 * free objects in addition to the regular freelist
178 * that requires the slab lock.
179 *
180 * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
181 * options set. This moves slab handling out of
182 * the fast path and disables lockless freelists.
183 */
184
185/*
186 * We could simply use migrate_disable()/enable() but as long as it's a
187 * function call even on !PREEMPT_RT, use inline preempt_disable() there.
188 */
189#ifndef CONFIG_PREEMPT_RT
190#define slub_get_cpu_ptr(var) get_cpu_ptr(var)
191#define slub_put_cpu_ptr(var) put_cpu_ptr(var)
192#define USE_LOCKLESS_FAST_PATH() (true)
193#else
194#define slub_get_cpu_ptr(var) \
195({ \
196 migrate_disable(); \
197 this_cpu_ptr(var); \
198})
199#define slub_put_cpu_ptr(var) \
200do { \
201 (void)(var); \
202 migrate_enable(); \
203} while (0)
204#define USE_LOCKLESS_FAST_PATH() (false)
205#endif
206
207#ifndef CONFIG_SLUB_TINY
208#define __fastpath_inline __always_inline
209#else
210#define __fastpath_inline
211#endif
212
213#ifdef CONFIG_SLUB_DEBUG
214#ifdef CONFIG_SLUB_DEBUG_ON
215DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
216#else
217DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
218#endif
219#endif /* CONFIG_SLUB_DEBUG */
220
221/* Structure holding parameters for get_partial() call chain */
222struct partial_context {
223 gfp_t flags;
224 unsigned int orig_size;
225 void *object;
226};
227
228static inline bool kmem_cache_debug(struct kmem_cache *s)
229{
230 return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
231}
232
233static inline bool slub_debug_orig_size(struct kmem_cache *s)
234{
235 return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
236 (s->flags & SLAB_KMALLOC));
237}
238
239void *fixup_red_left(struct kmem_cache *s, void *p)
240{
241 if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
242 p += s->red_left_pad;
243
244 return p;
245}
246
247static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
248{
249#ifdef CONFIG_SLUB_CPU_PARTIAL
250 return !kmem_cache_debug(s);
251#else
252 return false;
253#endif
254}
255
256/*
257 * Issues still to be resolved:
258 *
259 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
260 *
261 * - Variable sizing of the per node arrays
262 */
263
264/* Enable to log cmpxchg failures */
265#undef SLUB_DEBUG_CMPXCHG
266
267#ifndef CONFIG_SLUB_TINY
268/*
269 * Minimum number of partial slabs. These will be left on the partial
270 * lists even if they are empty. kmem_cache_shrink may reclaim them.
271 */
272#define MIN_PARTIAL 5
273
274/*
275 * Maximum number of desirable partial slabs.
276 * The existence of more partial slabs makes kmem_cache_shrink
277 * sort the partial list by the number of objects in use.
278 */
279#define MAX_PARTIAL 10
280#else
281#define MIN_PARTIAL 0
282#define MAX_PARTIAL 0
283#endif
284
285#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
286 SLAB_POISON | SLAB_STORE_USER)
287
288/*
289 * These debug flags cannot use CMPXCHG because there might be consistency
290 * issues when checking or reading debug information
291 */
292#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
293 SLAB_TRACE)
294
295
296/*
297 * Debugging flags that require metadata to be stored in the slab. These get
298 * disabled when slub_debug=O is used and a cache's min order increases with
299 * metadata.
300 */
301#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
302
303#define OO_SHIFT 16
304#define OO_MASK ((1 << OO_SHIFT) - 1)
305#define MAX_OBJS_PER_PAGE 32767 /* since slab.objects is u15 */
306
307/* Internal SLUB flags */
308/* Poison object */
309#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
310/* Use cmpxchg_double */
311
312#ifdef system_has_freelist_aba
313#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
314#else
315#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0U)
316#endif
317
318/*
319 * Tracking user of a slab.
320 */
321#define TRACK_ADDRS_COUNT 16
322struct track {
323 unsigned long addr; /* Called from address */
324#ifdef CONFIG_STACKDEPOT
325 depot_stack_handle_t handle;
326#endif
327 int cpu; /* Was running on cpu */
328 int pid; /* Pid context */
329 unsigned long when; /* When did the operation occur */
330};
331
332enum track_item { TRACK_ALLOC, TRACK_FREE };
333
334#ifdef SLAB_SUPPORTS_SYSFS
335static int sysfs_slab_add(struct kmem_cache *);
336static int sysfs_slab_alias(struct kmem_cache *, const char *);
337#else
338static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
339static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
340 { return 0; }
341#endif
342
343#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
344static void debugfs_slab_add(struct kmem_cache *);
345#else
346static inline void debugfs_slab_add(struct kmem_cache *s) { }
347#endif
348
349enum stat_item {
350 ALLOC_FASTPATH, /* Allocation from cpu slab */
351 ALLOC_SLOWPATH, /* Allocation by getting a new cpu slab */
352 FREE_FASTPATH, /* Free to cpu slab */
353 FREE_SLOWPATH, /* Freeing not to cpu slab */
354 FREE_FROZEN, /* Freeing to frozen slab */
355 FREE_ADD_PARTIAL, /* Freeing moves slab to partial list */
356 FREE_REMOVE_PARTIAL, /* Freeing removes last object */
357 ALLOC_FROM_PARTIAL, /* Cpu slab acquired from node partial list */
358 ALLOC_SLAB, /* Cpu slab acquired from page allocator */
359 ALLOC_REFILL, /* Refill cpu slab from slab freelist */
360 ALLOC_NODE_MISMATCH, /* Switching cpu slab */
361 FREE_SLAB, /* Slab freed to the page allocator */
362 CPUSLAB_FLUSH, /* Abandoning of the cpu slab */
363 DEACTIVATE_FULL, /* Cpu slab was full when deactivated */
364 DEACTIVATE_EMPTY, /* Cpu slab was empty when deactivated */
365 DEACTIVATE_TO_HEAD, /* Cpu slab was moved to the head of partials */
366 DEACTIVATE_TO_TAIL, /* Cpu slab was moved to the tail of partials */
367 DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
368 DEACTIVATE_BYPASS, /* Implicit deactivation */
369 ORDER_FALLBACK, /* Number of times fallback was necessary */
370 CMPXCHG_DOUBLE_CPU_FAIL,/* Failures of this_cpu_cmpxchg_double */
371 CMPXCHG_DOUBLE_FAIL, /* Failures of slab freelist update */
372 CPU_PARTIAL_ALLOC, /* Used cpu partial on alloc */
373 CPU_PARTIAL_FREE, /* Refill cpu partial on free */
374 CPU_PARTIAL_NODE, /* Refill cpu partial from node partial */
375 CPU_PARTIAL_DRAIN, /* Drain cpu partial to node partial */
376 NR_SLUB_STAT_ITEMS
377};
378
379#ifndef CONFIG_SLUB_TINY
380/*
381 * When changing the layout, make sure freelist and tid are still compatible
382 * with this_cpu_cmpxchg_double() alignment requirements.
383 */
384struct kmem_cache_cpu {
385 union {
386 struct {
387 void **freelist; /* Pointer to next available object */
388 unsigned long tid; /* Globally unique transaction id */
389 };
390 freelist_aba_t freelist_tid;
391 };
392 struct slab *slab; /* The slab from which we are allocating */
393#ifdef CONFIG_SLUB_CPU_PARTIAL
394 struct slab *partial; /* Partially allocated frozen slabs */
395#endif
396 local_lock_t lock; /* Protects the fields above */
397#ifdef CONFIG_SLUB_STATS
398 unsigned int stat[NR_SLUB_STAT_ITEMS];
399#endif
400};
401#endif /* CONFIG_SLUB_TINY */
402
403static inline void stat(const struct kmem_cache *s, enum stat_item si)
404{
405#ifdef CONFIG_SLUB_STATS
406 /*
407 * The rmw is racy on a preemptible kernel but this is acceptable, so
408 * avoid this_cpu_add()'s irq-disable overhead.
409 */
410 raw_cpu_inc(s->cpu_slab->stat[si]);
411#endif
412}
413
414static inline
415void stat_add(const struct kmem_cache *s, enum stat_item si, int v)
416{
417#ifdef CONFIG_SLUB_STATS
418 raw_cpu_add(s->cpu_slab->stat[si], v);
419#endif
420}
421
422/*
423 * The slab lists for all objects.
424 */
425struct kmem_cache_node {
426 spinlock_t list_lock;
427 unsigned long nr_partial;
428 struct list_head partial;
429#ifdef CONFIG_SLUB_DEBUG
430 atomic_long_t nr_slabs;
431 atomic_long_t total_objects;
432 struct list_head full;
433#endif
434};
435
436static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
437{
438 return s->node[node];
439}
440
441/*
442 * Iterator over all nodes. The body will be executed for each node that has
443 * a kmem_cache_node structure allocated (which is true for all online nodes)
444 */
445#define for_each_kmem_cache_node(__s, __node, __n) \
446 for (__node = 0; __node < nr_node_ids; __node++) \
447 if ((__n = get_node(__s, __node)))
448
449/*
450 * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
451 * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
452 * differ during memory hotplug/hotremove operations.
453 * Protected by slab_mutex.
454 */
455static nodemask_t slab_nodes;
456
457#ifndef CONFIG_SLUB_TINY
458/*
459 * Workqueue used for flush_cpu_slab().
460 */
461static struct workqueue_struct *flushwq;
462#endif
463
464/********************************************************************
465 * Core slab cache functions
466 *******************************************************************/
467
468/*
469 * freeptr_t represents a SLUB freelist pointer, which might be encoded
470 * and not dereferenceable if CONFIG_SLAB_FREELIST_HARDENED is enabled.
471 */
472typedef struct { unsigned long v; } freeptr_t;
473
474/*
475 * Returns freelist pointer (ptr). With hardening, this is obfuscated
476 * with an XOR of the address where the pointer is held and a per-cache
477 * random number.
478 */
479static inline freeptr_t freelist_ptr_encode(const struct kmem_cache *s,
480 void *ptr, unsigned long ptr_addr)
481{
482 unsigned long encoded;
483
484#ifdef CONFIG_SLAB_FREELIST_HARDENED
485 encoded = (unsigned long)ptr ^ s->random ^ swab(ptr_addr);
486#else
487 encoded = (unsigned long)ptr;
488#endif
489 return (freeptr_t){.v = encoded};
490}
491
492static inline void *freelist_ptr_decode(const struct kmem_cache *s,
493 freeptr_t ptr, unsigned long ptr_addr)
494{
495 void *decoded;
496
497#ifdef CONFIG_SLAB_FREELIST_HARDENED
498 decoded = (void *)(ptr.v ^ s->random ^ swab(ptr_addr));
499#else
500 decoded = (void *)ptr.v;
501#endif
502 return decoded;
503}
504
505static inline void *get_freepointer(struct kmem_cache *s, void *object)
506{
507 unsigned long ptr_addr;
508 freeptr_t p;
509
510 object = kasan_reset_tag(object);
511 ptr_addr = (unsigned long)object + s->offset;
512 p = *(freeptr_t *)(ptr_addr);
513 return freelist_ptr_decode(s, p, ptr_addr);
514}
515
516#ifndef CONFIG_SLUB_TINY
517static void prefetch_freepointer(const struct kmem_cache *s, void *object)
518{
519 prefetchw(object + s->offset);
520}
521#endif
522
523/*
524 * When running under KMSAN, get_freepointer_safe() may return an uninitialized
525 * pointer value in the case the current thread loses the race for the next
526 * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
527 * slab_alloc_node() will fail, so the uninitialized value won't be used, but
528 * KMSAN will still check all arguments of cmpxchg because of imperfect
529 * handling of inline assembly.
530 * To work around this problem, we apply __no_kmsan_checks to ensure that
531 * get_freepointer_safe() returns initialized memory.
532 */
533__no_kmsan_checks
534static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
535{
536 unsigned long freepointer_addr;
537 freeptr_t p;
538
539 if (!debug_pagealloc_enabled_static())
540 return get_freepointer(s, object);
541
542 object = kasan_reset_tag(object);
543 freepointer_addr = (unsigned long)object + s->offset;
544 copy_from_kernel_nofault(&p, (freeptr_t *)freepointer_addr, sizeof(p));
545 return freelist_ptr_decode(s, p, freepointer_addr);
546}
547
548static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
549{
550 unsigned long freeptr_addr = (unsigned long)object + s->offset;
551
552#ifdef CONFIG_SLAB_FREELIST_HARDENED
553 BUG_ON(object == fp); /* naive detection of double free or corruption */
554#endif
555
556 freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
557 *(freeptr_t *)freeptr_addr = freelist_ptr_encode(s, fp, freeptr_addr);
558}
559
560/* Loop over all objects in a slab */
561#define for_each_object(__p, __s, __addr, __objects) \
562 for (__p = fixup_red_left(__s, __addr); \
563 __p < (__addr) + (__objects) * (__s)->size; \
564 __p += (__s)->size)
565
566static inline unsigned int order_objects(unsigned int order, unsigned int size)
567{
568 return ((unsigned int)PAGE_SIZE << order) / size;
569}
570
571static inline struct kmem_cache_order_objects oo_make(unsigned int order,
572 unsigned int size)
573{
574 struct kmem_cache_order_objects x = {
575 (order << OO_SHIFT) + order_objects(order, size)
576 };
577
578 return x;
579}
580
581static inline unsigned int oo_order(struct kmem_cache_order_objects x)
582{
583 return x.x >> OO_SHIFT;
584}
585
586static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
587{
588 return x.x & OO_MASK;
589}
590
591#ifdef CONFIG_SLUB_CPU_PARTIAL
592static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
593{
594 unsigned int nr_slabs;
595
596 s->cpu_partial = nr_objects;
597
598 /*
599 * We take the number of objects but actually limit the number of
600 * slabs on the per cpu partial list, in order to limit excessive
601 * growth of the list. For simplicity we assume that the slabs will
602 * be half-full.
603 */
604 nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
605 s->cpu_partial_slabs = nr_slabs;
606}
607#else
608static inline void
609slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
610{
611}
612#endif /* CONFIG_SLUB_CPU_PARTIAL */
613
614/*
615 * Per slab locking using the pagelock
616 */
617static __always_inline void slab_lock(struct slab *slab)
618{
619 struct page *page = slab_page(slab);
620
621 VM_BUG_ON_PAGE(PageTail(page), page);
622 bit_spin_lock(PG_locked, &page->flags);
623}
624
625static __always_inline void slab_unlock(struct slab *slab)
626{
627 struct page *page = slab_page(slab);
628
629 VM_BUG_ON_PAGE(PageTail(page), page);
630 bit_spin_unlock(PG_locked, &page->flags);
631}
632
633static inline bool
634__update_freelist_fast(struct slab *slab,
635 void *freelist_old, unsigned long counters_old,
636 void *freelist_new, unsigned long counters_new)
637{
638#ifdef system_has_freelist_aba
639 freelist_aba_t old = { .freelist = freelist_old, .counter = counters_old };
640 freelist_aba_t new = { .freelist = freelist_new, .counter = counters_new };
641
642 return try_cmpxchg_freelist(&slab->freelist_counter.full, &old.full, new.full);
643#else
644 return false;
645#endif
646}
647
648static inline bool
649__update_freelist_slow(struct slab *slab,
650 void *freelist_old, unsigned long counters_old,
651 void *freelist_new, unsigned long counters_new)
652{
653 bool ret = false;
654
655 slab_lock(slab);
656 if (slab->freelist == freelist_old &&
657 slab->counters == counters_old) {
658 slab->freelist = freelist_new;
659 slab->counters = counters_new;
660 ret = true;
661 }
662 slab_unlock(slab);
663
664 return ret;
665}
666
667/*
668 * Interrupts must be disabled (for the fallback code to work right), typically
669 * by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
670 * part of bit_spin_lock(), is sufficient because the policy is not to allow any
671 * allocation/ free operation in hardirq context. Therefore nothing can
672 * interrupt the operation.
673 */
674static inline bool __slab_update_freelist(struct kmem_cache *s, struct slab *slab,
675 void *freelist_old, unsigned long counters_old,
676 void *freelist_new, unsigned long counters_new,
677 const char *n)
678{
679 bool ret;
680
681 if (USE_LOCKLESS_FAST_PATH())
682 lockdep_assert_irqs_disabled();
683
684 if (s->flags & __CMPXCHG_DOUBLE) {
685 ret = __update_freelist_fast(slab, freelist_old, counters_old,
686 freelist_new, counters_new);
687 } else {
688 ret = __update_freelist_slow(slab, freelist_old, counters_old,
689 freelist_new, counters_new);
690 }
691 if (likely(ret))
692 return true;
693
694 cpu_relax();
695 stat(s, CMPXCHG_DOUBLE_FAIL);
696
697#ifdef SLUB_DEBUG_CMPXCHG
698 pr_info("%s %s: cmpxchg double redo ", n, s->name);
699#endif
700
701 return false;
702}
703
704static inline bool slab_update_freelist(struct kmem_cache *s, struct slab *slab,
705 void *freelist_old, unsigned long counters_old,
706 void *freelist_new, unsigned long counters_new,
707 const char *n)
708{
709 bool ret;
710
711 if (s->flags & __CMPXCHG_DOUBLE) {
712 ret = __update_freelist_fast(slab, freelist_old, counters_old,
713 freelist_new, counters_new);
714 } else {
715 unsigned long flags;
716
717 local_irq_save(flags);
718 ret = __update_freelist_slow(slab, freelist_old, counters_old,
719 freelist_new, counters_new);
720 local_irq_restore(flags);
721 }
722 if (likely(ret))
723 return true;
724
725 cpu_relax();
726 stat(s, CMPXCHG_DOUBLE_FAIL);
727
728#ifdef SLUB_DEBUG_CMPXCHG
729 pr_info("%s %s: cmpxchg double redo ", n, s->name);
730#endif
731
732 return false;
733}
734
735#ifdef CONFIG_SLUB_DEBUG
736static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
737static DEFINE_SPINLOCK(object_map_lock);
738
739static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
740 struct slab *slab)
741{
742 void *addr = slab_address(slab);
743 void *p;
744
745 bitmap_zero(obj_map, slab->objects);
746
747 for (p = slab->freelist; p; p = get_freepointer(s, p))
748 set_bit(__obj_to_index(s, addr, p), obj_map);
749}
750
751#if IS_ENABLED(CONFIG_KUNIT)
752static bool slab_add_kunit_errors(void)
753{
754 struct kunit_resource *resource;
755
756 if (!kunit_get_current_test())
757 return false;
758
759 resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
760 if (!resource)
761 return false;
762
763 (*(int *)resource->data)++;
764 kunit_put_resource(resource);
765 return true;
766}
767#else
768static inline bool slab_add_kunit_errors(void) { return false; }
769#endif
770
771static inline unsigned int size_from_object(struct kmem_cache *s)
772{
773 if (s->flags & SLAB_RED_ZONE)
774 return s->size - s->red_left_pad;
775
776 return s->size;
777}
778
779static inline void *restore_red_left(struct kmem_cache *s, void *p)
780{
781 if (s->flags & SLAB_RED_ZONE)
782 p -= s->red_left_pad;
783
784 return p;
785}
786
787/*
788 * Debug settings:
789 */
790#if defined(CONFIG_SLUB_DEBUG_ON)
791static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
792#else
793static slab_flags_t slub_debug;
794#endif
795
796static char *slub_debug_string;
797static int disable_higher_order_debug;
798
799/*
800 * slub is about to manipulate internal object metadata. This memory lies
801 * outside the range of the allocated object, so accessing it would normally
802 * be reported by kasan as a bounds error. metadata_access_enable() is used
803 * to tell kasan that these accesses are OK.
804 */
805static inline void metadata_access_enable(void)
806{
807 kasan_disable_current();
808}
809
810static inline void metadata_access_disable(void)
811{
812 kasan_enable_current();
813}
814
815/*
816 * Object debugging
817 */
818
819/* Verify that a pointer has an address that is valid within a slab page */
820static inline int check_valid_pointer(struct kmem_cache *s,
821 struct slab *slab, void *object)
822{
823 void *base;
824
825 if (!object)
826 return 1;
827
828 base = slab_address(slab);
829 object = kasan_reset_tag(object);
830 object = restore_red_left(s, object);
831 if (object < base || object >= base + slab->objects * s->size ||
832 (object - base) % s->size) {
833 return 0;
834 }
835
836 return 1;
837}
838
839static void print_section(char *level, char *text, u8 *addr,
840 unsigned int length)
841{
842 metadata_access_enable();
843 print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
844 16, 1, kasan_reset_tag((void *)addr), length, 1);
845 metadata_access_disable();
846}
847
848/*
849 * See comment in calculate_sizes().
850 */
851static inline bool freeptr_outside_object(struct kmem_cache *s)
852{
853 return s->offset >= s->inuse;
854}
855
856/*
857 * Return offset of the end of info block which is inuse + free pointer if
858 * not overlapping with object.
859 */
860static inline unsigned int get_info_end(struct kmem_cache *s)
861{
862 if (freeptr_outside_object(s))
863 return s->inuse + sizeof(void *);
864 else
865 return s->inuse;
866}
867
868static struct track *get_track(struct kmem_cache *s, void *object,
869 enum track_item alloc)
870{
871 struct track *p;
872
873 p = object + get_info_end(s);
874
875 return kasan_reset_tag(p + alloc);
876}
877
878#ifdef CONFIG_STACKDEPOT
879static noinline depot_stack_handle_t set_track_prepare(void)
880{
881 depot_stack_handle_t handle;
882 unsigned long entries[TRACK_ADDRS_COUNT];
883 unsigned int nr_entries;
884
885 nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
886 handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
887
888 return handle;
889}
890#else
891static inline depot_stack_handle_t set_track_prepare(void)
892{
893 return 0;
894}
895#endif
896
897static void set_track_update(struct kmem_cache *s, void *object,
898 enum track_item alloc, unsigned long addr,
899 depot_stack_handle_t handle)
900{
901 struct track *p = get_track(s, object, alloc);
902
903#ifdef CONFIG_STACKDEPOT
904 p->handle = handle;
905#endif
906 p->addr = addr;
907 p->cpu = smp_processor_id();
908 p->pid = current->pid;
909 p->when = jiffies;
910}
911
912static __always_inline void set_track(struct kmem_cache *s, void *object,
913 enum track_item alloc, unsigned long addr)
914{
915 depot_stack_handle_t handle = set_track_prepare();
916
917 set_track_update(s, object, alloc, addr, handle);
918}
919
920static void init_tracking(struct kmem_cache *s, void *object)
921{
922 struct track *p;
923
924 if (!(s->flags & SLAB_STORE_USER))
925 return;
926
927 p = get_track(s, object, TRACK_ALLOC);
928 memset(p, 0, 2*sizeof(struct track));
929}
930
931static void print_track(const char *s, struct track *t, unsigned long pr_time)
932{
933 depot_stack_handle_t handle __maybe_unused;
934
935 if (!t->addr)
936 return;
937
938 pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
939 s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
940#ifdef CONFIG_STACKDEPOT
941 handle = READ_ONCE(t->handle);
942 if (handle)
943 stack_depot_print(handle);
944 else
945 pr_err("object allocation/free stack trace missing\n");
946#endif
947}
948
949void print_tracking(struct kmem_cache *s, void *object)
950{
951 unsigned long pr_time = jiffies;
952 if (!(s->flags & SLAB_STORE_USER))
953 return;
954
955 print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
956 print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
957}
958
959static void print_slab_info(const struct slab *slab)
960{
961 struct folio *folio = (struct folio *)slab_folio(slab);
962
963 pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
964 slab, slab->objects, slab->inuse, slab->freelist,
965 folio_flags(folio, 0));
966}
967
968/*
969 * kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
970 * family will round up the real request size to these fixed ones, so
971 * there could be an extra area than what is requested. Save the original
972 * request size in the meta data area, for better debug and sanity check.
973 */
974static inline void set_orig_size(struct kmem_cache *s,
975 void *object, unsigned int orig_size)
976{
977 void *p = kasan_reset_tag(object);
978 unsigned int kasan_meta_size;
979
980 if (!slub_debug_orig_size(s))
981 return;
982
983 /*
984 * KASAN can save its free meta data inside of the object at offset 0.
985 * If this meta data size is larger than 'orig_size', it will overlap
986 * the data redzone in [orig_size+1, object_size]. Thus, we adjust
987 * 'orig_size' to be as at least as big as KASAN's meta data.
988 */
989 kasan_meta_size = kasan_metadata_size(s, true);
990 if (kasan_meta_size > orig_size)
991 orig_size = kasan_meta_size;
992
993 p += get_info_end(s);
994 p += sizeof(struct track) * 2;
995
996 *(unsigned int *)p = orig_size;
997}
998
999static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
1000{
1001 void *p = kasan_reset_tag(object);
1002
1003 if (!slub_debug_orig_size(s))
1004 return s->object_size;
1005
1006 p += get_info_end(s);
1007 p += sizeof(struct track) * 2;
1008
1009 return *(unsigned int *)p;
1010}
1011
1012void skip_orig_size_check(struct kmem_cache *s, const void *object)
1013{
1014 set_orig_size(s, (void *)object, s->object_size);
1015}
1016
1017static void slab_bug(struct kmem_cache *s, char *fmt, ...)
1018{
1019 struct va_format vaf;
1020 va_list args;
1021
1022 va_start(args, fmt);
1023 vaf.fmt = fmt;
1024 vaf.va = &args;
1025 pr_err("=============================================================================\n");
1026 pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
1027 pr_err("-----------------------------------------------------------------------------\n\n");
1028 va_end(args);
1029}
1030
1031__printf(2, 3)
1032static void slab_fix(struct kmem_cache *s, char *fmt, ...)
1033{
1034 struct va_format vaf;
1035 va_list args;
1036
1037 if (slab_add_kunit_errors())
1038 return;
1039
1040 va_start(args, fmt);
1041 vaf.fmt = fmt;
1042 vaf.va = &args;
1043 pr_err("FIX %s: %pV\n", s->name, &vaf);
1044 va_end(args);
1045}
1046
1047static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
1048{
1049 unsigned int off; /* Offset of last byte */
1050 u8 *addr = slab_address(slab);
1051
1052 print_tracking(s, p);
1053
1054 print_slab_info(slab);
1055
1056 pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
1057 p, p - addr, get_freepointer(s, p));
1058
1059 if (s->flags & SLAB_RED_ZONE)
1060 print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
1061 s->red_left_pad);
1062 else if (p > addr + 16)
1063 print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
1064
1065 print_section(KERN_ERR, "Object ", p,
1066 min_t(unsigned int, s->object_size, PAGE_SIZE));
1067 if (s->flags & SLAB_RED_ZONE)
1068 print_section(KERN_ERR, "Redzone ", p + s->object_size,
1069 s->inuse - s->object_size);
1070
1071 off = get_info_end(s);
1072
1073 if (s->flags & SLAB_STORE_USER)
1074 off += 2 * sizeof(struct track);
1075
1076 if (slub_debug_orig_size(s))
1077 off += sizeof(unsigned int);
1078
1079 off += kasan_metadata_size(s, false);
1080
1081 if (off != size_from_object(s))
1082 /* Beginning of the filler is the free pointer */
1083 print_section(KERN_ERR, "Padding ", p + off,
1084 size_from_object(s) - off);
1085
1086 dump_stack();
1087}
1088
1089static void object_err(struct kmem_cache *s, struct slab *slab,
1090 u8 *object, char *reason)
1091{
1092 if (slab_add_kunit_errors())
1093 return;
1094
1095 slab_bug(s, "%s", reason);
1096 print_trailer(s, slab, object);
1097 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1098}
1099
1100static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1101 void **freelist, void *nextfree)
1102{
1103 if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
1104 !check_valid_pointer(s, slab, nextfree) && freelist) {
1105 object_err(s, slab, *freelist, "Freechain corrupt");
1106 *freelist = NULL;
1107 slab_fix(s, "Isolate corrupted freechain");
1108 return true;
1109 }
1110
1111 return false;
1112}
1113
1114static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
1115 const char *fmt, ...)
1116{
1117 va_list args;
1118 char buf[100];
1119
1120 if (slab_add_kunit_errors())
1121 return;
1122
1123 va_start(args, fmt);
1124 vsnprintf(buf, sizeof(buf), fmt, args);
1125 va_end(args);
1126 slab_bug(s, "%s", buf);
1127 print_slab_info(slab);
1128 dump_stack();
1129 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1130}
1131
1132static void init_object(struct kmem_cache *s, void *object, u8 val)
1133{
1134 u8 *p = kasan_reset_tag(object);
1135 unsigned int poison_size = s->object_size;
1136
1137 if (s->flags & SLAB_RED_ZONE) {
1138 memset(p - s->red_left_pad, val, s->red_left_pad);
1139
1140 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1141 /*
1142 * Redzone the extra allocated space by kmalloc than
1143 * requested, and the poison size will be limited to
1144 * the original request size accordingly.
1145 */
1146 poison_size = get_orig_size(s, object);
1147 }
1148 }
1149
1150 if (s->flags & __OBJECT_POISON) {
1151 memset(p, POISON_FREE, poison_size - 1);
1152 p[poison_size - 1] = POISON_END;
1153 }
1154
1155 if (s->flags & SLAB_RED_ZONE)
1156 memset(p + poison_size, val, s->inuse - poison_size);
1157}
1158
1159static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
1160 void *from, void *to)
1161{
1162 slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
1163 memset(from, data, to - from);
1164}
1165
1166static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
1167 u8 *object, char *what,
1168 u8 *start, unsigned int value, unsigned int bytes)
1169{
1170 u8 *fault;
1171 u8 *end;
1172 u8 *addr = slab_address(slab);
1173
1174 metadata_access_enable();
1175 fault = memchr_inv(kasan_reset_tag(start), value, bytes);
1176 metadata_access_disable();
1177 if (!fault)
1178 return 1;
1179
1180 end = start + bytes;
1181 while (end > fault && end[-1] == value)
1182 end--;
1183
1184 if (slab_add_kunit_errors())
1185 goto skip_bug_print;
1186
1187 slab_bug(s, "%s overwritten", what);
1188 pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
1189 fault, end - 1, fault - addr,
1190 fault[0], value);
1191 print_trailer(s, slab, object);
1192 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
1193
1194skip_bug_print:
1195 restore_bytes(s, what, value, fault, end);
1196 return 0;
1197}
1198
1199/*
1200 * Object layout:
1201 *
1202 * object address
1203 * Bytes of the object to be managed.
1204 * If the freepointer may overlay the object then the free
1205 * pointer is at the middle of the object.
1206 *
1207 * Poisoning uses 0x6b (POISON_FREE) and the last byte is
1208 * 0xa5 (POISON_END)
1209 *
1210 * object + s->object_size
1211 * Padding to reach word boundary. This is also used for Redzoning.
1212 * Padding is extended by another word if Redzoning is enabled and
1213 * object_size == inuse.
1214 *
1215 * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
1216 * 0xcc (RED_ACTIVE) for objects in use.
1217 *
1218 * object + s->inuse
1219 * Meta data starts here.
1220 *
1221 * A. Free pointer (if we cannot overwrite object on free)
1222 * B. Tracking data for SLAB_STORE_USER
1223 * C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
1224 * D. Padding to reach required alignment boundary or at minimum
1225 * one word if debugging is on to be able to detect writes
1226 * before the word boundary.
1227 *
1228 * Padding is done using 0x5a (POISON_INUSE)
1229 *
1230 * object + s->size
1231 * Nothing is used beyond s->size.
1232 *
1233 * If slabcaches are merged then the object_size and inuse boundaries are mostly
1234 * ignored. And therefore no slab options that rely on these boundaries
1235 * may be used with merged slabcaches.
1236 */
1237
1238static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
1239{
1240 unsigned long off = get_info_end(s); /* The end of info */
1241
1242 if (s->flags & SLAB_STORE_USER) {
1243 /* We also have user information there */
1244 off += 2 * sizeof(struct track);
1245
1246 if (s->flags & SLAB_KMALLOC)
1247 off += sizeof(unsigned int);
1248 }
1249
1250 off += kasan_metadata_size(s, false);
1251
1252 if (size_from_object(s) == off)
1253 return 1;
1254
1255 return check_bytes_and_report(s, slab, p, "Object padding",
1256 p + off, POISON_INUSE, size_from_object(s) - off);
1257}
1258
1259/* Check the pad bytes at the end of a slab page */
1260static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
1261{
1262 u8 *start;
1263 u8 *fault;
1264 u8 *end;
1265 u8 *pad;
1266 int length;
1267 int remainder;
1268
1269 if (!(s->flags & SLAB_POISON))
1270 return;
1271
1272 start = slab_address(slab);
1273 length = slab_size(slab);
1274 end = start + length;
1275 remainder = length % s->size;
1276 if (!remainder)
1277 return;
1278
1279 pad = end - remainder;
1280 metadata_access_enable();
1281 fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
1282 metadata_access_disable();
1283 if (!fault)
1284 return;
1285 while (end > fault && end[-1] == POISON_INUSE)
1286 end--;
1287
1288 slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
1289 fault, end - 1, fault - start);
1290 print_section(KERN_ERR, "Padding ", pad, remainder);
1291
1292 restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
1293}
1294
1295static int check_object(struct kmem_cache *s, struct slab *slab,
1296 void *object, u8 val)
1297{
1298 u8 *p = object;
1299 u8 *endobject = object + s->object_size;
1300 unsigned int orig_size, kasan_meta_size;
1301
1302 if (s->flags & SLAB_RED_ZONE) {
1303 if (!check_bytes_and_report(s, slab, object, "Left Redzone",
1304 object - s->red_left_pad, val, s->red_left_pad))
1305 return 0;
1306
1307 if (!check_bytes_and_report(s, slab, object, "Right Redzone",
1308 endobject, val, s->inuse - s->object_size))
1309 return 0;
1310
1311 if (slub_debug_orig_size(s) && val == SLUB_RED_ACTIVE) {
1312 orig_size = get_orig_size(s, object);
1313
1314 if (s->object_size > orig_size &&
1315 !check_bytes_and_report(s, slab, object,
1316 "kmalloc Redzone", p + orig_size,
1317 val, s->object_size - orig_size)) {
1318 return 0;
1319 }
1320 }
1321 } else {
1322 if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
1323 check_bytes_and_report(s, slab, p, "Alignment padding",
1324 endobject, POISON_INUSE,
1325 s->inuse - s->object_size);
1326 }
1327 }
1328
1329 if (s->flags & SLAB_POISON) {
1330 if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON)) {
1331 /*
1332 * KASAN can save its free meta data inside of the
1333 * object at offset 0. Thus, skip checking the part of
1334 * the redzone that overlaps with the meta data.
1335 */
1336 kasan_meta_size = kasan_metadata_size(s, true);
1337 if (kasan_meta_size < s->object_size - 1 &&
1338 !check_bytes_and_report(s, slab, p, "Poison",
1339 p + kasan_meta_size, POISON_FREE,
1340 s->object_size - kasan_meta_size - 1))
1341 return 0;
1342 if (kasan_meta_size < s->object_size &&
1343 !check_bytes_and_report(s, slab, p, "End Poison",
1344 p + s->object_size - 1, POISON_END, 1))
1345 return 0;
1346 }
1347 /*
1348 * check_pad_bytes cleans up on its own.
1349 */
1350 check_pad_bytes(s, slab, p);
1351 }
1352
1353 if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
1354 /*
1355 * Object and freepointer overlap. Cannot check
1356 * freepointer while object is allocated.
1357 */
1358 return 1;
1359
1360 /* Check free pointer validity */
1361 if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
1362 object_err(s, slab, p, "Freepointer corrupt");
1363 /*
1364 * No choice but to zap it and thus lose the remainder
1365 * of the free objects in this slab. May cause
1366 * another error because the object count is now wrong.
1367 */
1368 set_freepointer(s, p, NULL);
1369 return 0;
1370 }
1371 return 1;
1372}
1373
1374static int check_slab(struct kmem_cache *s, struct slab *slab)
1375{
1376 int maxobj;
1377
1378 if (!folio_test_slab(slab_folio(slab))) {
1379 slab_err(s, slab, "Not a valid slab page");
1380 return 0;
1381 }
1382
1383 maxobj = order_objects(slab_order(slab), s->size);
1384 if (slab->objects > maxobj) {
1385 slab_err(s, slab, "objects %u > max %u",
1386 slab->objects, maxobj);
1387 return 0;
1388 }
1389 if (slab->inuse > slab->objects) {
1390 slab_err(s, slab, "inuse %u > max %u",
1391 slab->inuse, slab->objects);
1392 return 0;
1393 }
1394 /* Slab_pad_check fixes things up after itself */
1395 slab_pad_check(s, slab);
1396 return 1;
1397}
1398
1399/*
1400 * Determine if a certain object in a slab is on the freelist. Must hold the
1401 * slab lock to guarantee that the chains are in a consistent state.
1402 */
1403static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
1404{
1405 int nr = 0;
1406 void *fp;
1407 void *object = NULL;
1408 int max_objects;
1409
1410 fp = slab->freelist;
1411 while (fp && nr <= slab->objects) {
1412 if (fp == search)
1413 return 1;
1414 if (!check_valid_pointer(s, slab, fp)) {
1415 if (object) {
1416 object_err(s, slab, object,
1417 "Freechain corrupt");
1418 set_freepointer(s, object, NULL);
1419 } else {
1420 slab_err(s, slab, "Freepointer corrupt");
1421 slab->freelist = NULL;
1422 slab->inuse = slab->objects;
1423 slab_fix(s, "Freelist cleared");
1424 return 0;
1425 }
1426 break;
1427 }
1428 object = fp;
1429 fp = get_freepointer(s, object);
1430 nr++;
1431 }
1432
1433 max_objects = order_objects(slab_order(slab), s->size);
1434 if (max_objects > MAX_OBJS_PER_PAGE)
1435 max_objects = MAX_OBJS_PER_PAGE;
1436
1437 if (slab->objects != max_objects) {
1438 slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
1439 slab->objects, max_objects);
1440 slab->objects = max_objects;
1441 slab_fix(s, "Number of objects adjusted");
1442 }
1443 if (slab->inuse != slab->objects - nr) {
1444 slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
1445 slab->inuse, slab->objects - nr);
1446 slab->inuse = slab->objects - nr;
1447 slab_fix(s, "Object count adjusted");
1448 }
1449 return search == NULL;
1450}
1451
1452static void trace(struct kmem_cache *s, struct slab *slab, void *object,
1453 int alloc)
1454{
1455 if (s->flags & SLAB_TRACE) {
1456 pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
1457 s->name,
1458 alloc ? "alloc" : "free",
1459 object, slab->inuse,
1460 slab->freelist);
1461
1462 if (!alloc)
1463 print_section(KERN_INFO, "Object ", (void *)object,
1464 s->object_size);
1465
1466 dump_stack();
1467 }
1468}
1469
1470/*
1471 * Tracking of fully allocated slabs for debugging purposes.
1472 */
1473static void add_full(struct kmem_cache *s,
1474 struct kmem_cache_node *n, struct slab *slab)
1475{
1476 if (!(s->flags & SLAB_STORE_USER))
1477 return;
1478
1479 lockdep_assert_held(&n->list_lock);
1480 list_add(&slab->slab_list, &n->full);
1481}
1482
1483static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
1484{
1485 if (!(s->flags & SLAB_STORE_USER))
1486 return;
1487
1488 lockdep_assert_held(&n->list_lock);
1489 list_del(&slab->slab_list);
1490}
1491
1492static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1493{
1494 return atomic_long_read(&n->nr_slabs);
1495}
1496
1497static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1498{
1499 struct kmem_cache_node *n = get_node(s, node);
1500
1501 /*
1502 * May be called early in order to allocate a slab for the
1503 * kmem_cache_node structure. Solve the chicken-egg
1504 * dilemma by deferring the increment of the count during
1505 * bootstrap (see early_kmem_cache_node_alloc).
1506 */
1507 if (likely(n)) {
1508 atomic_long_inc(&n->nr_slabs);
1509 atomic_long_add(objects, &n->total_objects);
1510 }
1511}
1512static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1513{
1514 struct kmem_cache_node *n = get_node(s, node);
1515
1516 atomic_long_dec(&n->nr_slabs);
1517 atomic_long_sub(objects, &n->total_objects);
1518}
1519
1520/* Object debug checks for alloc/free paths */
1521static void setup_object_debug(struct kmem_cache *s, void *object)
1522{
1523 if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
1524 return;
1525
1526 init_object(s, object, SLUB_RED_INACTIVE);
1527 init_tracking(s, object);
1528}
1529
1530static
1531void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
1532{
1533 if (!kmem_cache_debug_flags(s, SLAB_POISON))
1534 return;
1535
1536 metadata_access_enable();
1537 memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
1538 metadata_access_disable();
1539}
1540
1541static inline int alloc_consistency_checks(struct kmem_cache *s,
1542 struct slab *slab, void *object)
1543{
1544 if (!check_slab(s, slab))
1545 return 0;
1546
1547 if (!check_valid_pointer(s, slab, object)) {
1548 object_err(s, slab, object, "Freelist Pointer check fails");
1549 return 0;
1550 }
1551
1552 if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
1553 return 0;
1554
1555 return 1;
1556}
1557
1558static noinline bool alloc_debug_processing(struct kmem_cache *s,
1559 struct slab *slab, void *object, int orig_size)
1560{
1561 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
1562 if (!alloc_consistency_checks(s, slab, object))
1563 goto bad;
1564 }
1565
1566 /* Success. Perform special debug activities for allocs */
1567 trace(s, slab, object, 1);
1568 set_orig_size(s, object, orig_size);
1569 init_object(s, object, SLUB_RED_ACTIVE);
1570 return true;
1571
1572bad:
1573 if (folio_test_slab(slab_folio(slab))) {
1574 /*
1575 * If this is a slab page then lets do the best we can
1576 * to avoid issues in the future. Marking all objects
1577 * as used avoids touching the remaining objects.
1578 */
1579 slab_fix(s, "Marking all objects used");
1580 slab->inuse = slab->objects;
1581 slab->freelist = NULL;
1582 }
1583 return false;
1584}
1585
1586static inline int free_consistency_checks(struct kmem_cache *s,
1587 struct slab *slab, void *object, unsigned long addr)
1588{
1589 if (!check_valid_pointer(s, slab, object)) {
1590 slab_err(s, slab, "Invalid object pointer 0x%p", object);
1591 return 0;
1592 }
1593
1594 if (on_freelist(s, slab, object)) {
1595 object_err(s, slab, object, "Object already free");
1596 return 0;
1597 }
1598
1599 if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
1600 return 0;
1601
1602 if (unlikely(s != slab->slab_cache)) {
1603 if (!folio_test_slab(slab_folio(slab))) {
1604 slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
1605 object);
1606 } else if (!slab->slab_cache) {
1607 pr_err("SLUB <none>: no slab for object 0x%p.\n",
1608 object);
1609 dump_stack();
1610 } else
1611 object_err(s, slab, object,
1612 "page slab pointer corrupt.");
1613 return 0;
1614 }
1615 return 1;
1616}
1617
1618/*
1619 * Parse a block of slub_debug options. Blocks are delimited by ';'
1620 *
1621 * @str: start of block
1622 * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
1623 * @slabs: return start of list of slabs, or NULL when there's no list
1624 * @init: assume this is initial parsing and not per-kmem-create parsing
1625 *
1626 * returns the start of next block if there's any, or NULL
1627 */
1628static char *
1629parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
1630{
1631 bool higher_order_disable = false;
1632
1633 /* Skip any completely empty blocks */
1634 while (*str && *str == ';')
1635 str++;
1636
1637 if (*str == ',') {
1638 /*
1639 * No options but restriction on slabs. This means full
1640 * debugging for slabs matching a pattern.
1641 */
1642 *flags = DEBUG_DEFAULT_FLAGS;
1643 goto check_slabs;
1644 }
1645 *flags = 0;
1646
1647 /* Determine which debug features should be switched on */
1648 for (; *str && *str != ',' && *str != ';'; str++) {
1649 switch (tolower(*str)) {
1650 case '-':
1651 *flags = 0;
1652 break;
1653 case 'f':
1654 *flags |= SLAB_CONSISTENCY_CHECKS;
1655 break;
1656 case 'z':
1657 *flags |= SLAB_RED_ZONE;
1658 break;
1659 case 'p':
1660 *flags |= SLAB_POISON;
1661 break;
1662 case 'u':
1663 *flags |= SLAB_STORE_USER;
1664 break;
1665 case 't':
1666 *flags |= SLAB_TRACE;
1667 break;
1668 case 'a':
1669 *flags |= SLAB_FAILSLAB;
1670 break;
1671 case 'o':
1672 /*
1673 * Avoid enabling debugging on caches if its minimum
1674 * order would increase as a result.
1675 */
1676 higher_order_disable = true;
1677 break;
1678 default:
1679 if (init)
1680 pr_err("slub_debug option '%c' unknown. skipped\n", *str);
1681 }
1682 }
1683check_slabs:
1684 if (*str == ',')
1685 *slabs = ++str;
1686 else
1687 *slabs = NULL;
1688
1689 /* Skip over the slab list */
1690 while (*str && *str != ';')
1691 str++;
1692
1693 /* Skip any completely empty blocks */
1694 while (*str && *str == ';')
1695 str++;
1696
1697 if (init && higher_order_disable)
1698 disable_higher_order_debug = 1;
1699
1700 if (*str)
1701 return str;
1702 else
1703 return NULL;
1704}
1705
1706static int __init setup_slub_debug(char *str)
1707{
1708 slab_flags_t flags;
1709 slab_flags_t global_flags;
1710 char *saved_str;
1711 char *slab_list;
1712 bool global_slub_debug_changed = false;
1713 bool slab_list_specified = false;
1714
1715 global_flags = DEBUG_DEFAULT_FLAGS;
1716 if (*str++ != '=' || !*str)
1717 /*
1718 * No options specified. Switch on full debugging.
1719 */
1720 goto out;
1721
1722 saved_str = str;
1723 while (str) {
1724 str = parse_slub_debug_flags(str, &flags, &slab_list, true);
1725
1726 if (!slab_list) {
1727 global_flags = flags;
1728 global_slub_debug_changed = true;
1729 } else {
1730 slab_list_specified = true;
1731 if (flags & SLAB_STORE_USER)
1732 stack_depot_request_early_init();
1733 }
1734 }
1735
1736 /*
1737 * For backwards compatibility, a single list of flags with list of
1738 * slabs means debugging is only changed for those slabs, so the global
1739 * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
1740 * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
1741 * long as there is no option specifying flags without a slab list.
1742 */
1743 if (slab_list_specified) {
1744 if (!global_slub_debug_changed)
1745 global_flags = slub_debug;
1746 slub_debug_string = saved_str;
1747 }
1748out:
1749 slub_debug = global_flags;
1750 if (slub_debug & SLAB_STORE_USER)
1751 stack_depot_request_early_init();
1752 if (slub_debug != 0 || slub_debug_string)
1753 static_branch_enable(&slub_debug_enabled);
1754 else
1755 static_branch_disable(&slub_debug_enabled);
1756 if ((static_branch_unlikely(&init_on_alloc) ||
1757 static_branch_unlikely(&init_on_free)) &&
1758 (slub_debug & SLAB_POISON))
1759 pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
1760 return 1;
1761}
1762
1763__setup("slub_debug", setup_slub_debug);
1764
1765/*
1766 * kmem_cache_flags - apply debugging options to the cache
1767 * @object_size: the size of an object without meta data
1768 * @flags: flags to set
1769 * @name: name of the cache
1770 *
1771 * Debug option(s) are applied to @flags. In addition to the debug
1772 * option(s), if a slab name (or multiple) is specified i.e.
1773 * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
1774 * then only the select slabs will receive the debug option(s).
1775 */
1776slab_flags_t kmem_cache_flags(unsigned int object_size,
1777 slab_flags_t flags, const char *name)
1778{
1779 char *iter;
1780 size_t len;
1781 char *next_block;
1782 slab_flags_t block_flags;
1783 slab_flags_t slub_debug_local = slub_debug;
1784
1785 if (flags & SLAB_NO_USER_FLAGS)
1786 return flags;
1787
1788 /*
1789 * If the slab cache is for debugging (e.g. kmemleak) then
1790 * don't store user (stack trace) information by default,
1791 * but let the user enable it via the command line below.
1792 */
1793 if (flags & SLAB_NOLEAKTRACE)
1794 slub_debug_local &= ~SLAB_STORE_USER;
1795
1796 len = strlen(name);
1797 next_block = slub_debug_string;
1798 /* Go through all blocks of debug options, see if any matches our slab's name */
1799 while (next_block) {
1800 next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
1801 if (!iter)
1802 continue;
1803 /* Found a block that has a slab list, search it */
1804 while (*iter) {
1805 char *end, *glob;
1806 size_t cmplen;
1807
1808 end = strchrnul(iter, ',');
1809 if (next_block && next_block < end)
1810 end = next_block - 1;
1811
1812 glob = strnchr(iter, end - iter, '*');
1813 if (glob)
1814 cmplen = glob - iter;
1815 else
1816 cmplen = max_t(size_t, len, (end - iter));
1817
1818 if (!strncmp(name, iter, cmplen)) {
1819 flags |= block_flags;
1820 return flags;
1821 }
1822
1823 if (!*end || *end == ';')
1824 break;
1825 iter = end + 1;
1826 }
1827 }
1828
1829 return flags | slub_debug_local;
1830}
1831#else /* !CONFIG_SLUB_DEBUG */
1832static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
1833static inline
1834void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
1835
1836static inline bool alloc_debug_processing(struct kmem_cache *s,
1837 struct slab *slab, void *object, int orig_size) { return true; }
1838
1839static inline bool free_debug_processing(struct kmem_cache *s,
1840 struct slab *slab, void *head, void *tail, int *bulk_cnt,
1841 unsigned long addr, depot_stack_handle_t handle) { return true; }
1842
1843static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
1844static inline int check_object(struct kmem_cache *s, struct slab *slab,
1845 void *object, u8 val) { return 1; }
1846static inline depot_stack_handle_t set_track_prepare(void) { return 0; }
1847static inline void set_track(struct kmem_cache *s, void *object,
1848 enum track_item alloc, unsigned long addr) {}
1849static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1850 struct slab *slab) {}
1851static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
1852 struct slab *slab) {}
1853slab_flags_t kmem_cache_flags(unsigned int object_size,
1854 slab_flags_t flags, const char *name)
1855{
1856 return flags;
1857}
1858#define slub_debug 0
1859
1860#define disable_higher_order_debug 0
1861
1862static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1863 { return 0; }
1864static inline void inc_slabs_node(struct kmem_cache *s, int node,
1865 int objects) {}
1866static inline void dec_slabs_node(struct kmem_cache *s, int node,
1867 int objects) {}
1868
1869#ifndef CONFIG_SLUB_TINY
1870static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
1871 void **freelist, void *nextfree)
1872{
1873 return false;
1874}
1875#endif
1876#endif /* CONFIG_SLUB_DEBUG */
1877
1878static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s)
1879{
1880 return (s->flags & SLAB_RECLAIM_ACCOUNT) ?
1881 NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B;
1882}
1883
1884#ifdef CONFIG_MEMCG_KMEM
1885static inline void memcg_free_slab_cgroups(struct slab *slab)
1886{
1887 kfree(slab_objcgs(slab));
1888 slab->memcg_data = 0;
1889}
1890
1891static inline size_t obj_full_size(struct kmem_cache *s)
1892{
1893 /*
1894 * For each accounted object there is an extra space which is used
1895 * to store obj_cgroup membership. Charge it too.
1896 */
1897 return s->size + sizeof(struct obj_cgroup *);
1898}
1899
1900/*
1901 * Returns false if the allocation should fail.
1902 */
1903static bool __memcg_slab_pre_alloc_hook(struct kmem_cache *s,
1904 struct list_lru *lru,
1905 struct obj_cgroup **objcgp,
1906 size_t objects, gfp_t flags)
1907{
1908 /*
1909 * The obtained objcg pointer is safe to use within the current scope,
1910 * defined by current task or set_active_memcg() pair.
1911 * obj_cgroup_get() is used to get a permanent reference.
1912 */
1913 struct obj_cgroup *objcg = current_obj_cgroup();
1914 if (!objcg)
1915 return true;
1916
1917 if (lru) {
1918 int ret;
1919 struct mem_cgroup *memcg;
1920
1921 memcg = get_mem_cgroup_from_objcg(objcg);
1922 ret = memcg_list_lru_alloc(memcg, lru, flags);
1923 css_put(&memcg->css);
1924
1925 if (ret)
1926 return false;
1927 }
1928
1929 if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s)))
1930 return false;
1931
1932 *objcgp = objcg;
1933 return true;
1934}
1935
1936/*
1937 * Returns false if the allocation should fail.
1938 */
1939static __fastpath_inline
1940bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, struct list_lru *lru,
1941 struct obj_cgroup **objcgp, size_t objects,
1942 gfp_t flags)
1943{
1944 if (!memcg_kmem_online())
1945 return true;
1946
1947 if (likely(!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)))
1948 return true;
1949
1950 return likely(__memcg_slab_pre_alloc_hook(s, lru, objcgp, objects,
1951 flags));
1952}
1953
1954static void __memcg_slab_post_alloc_hook(struct kmem_cache *s,
1955 struct obj_cgroup *objcg,
1956 gfp_t flags, size_t size,
1957 void **p)
1958{
1959 struct slab *slab;
1960 unsigned long off;
1961 size_t i;
1962
1963 flags &= gfp_allowed_mask;
1964
1965 for (i = 0; i < size; i++) {
1966 if (likely(p[i])) {
1967 slab = virt_to_slab(p[i]);
1968
1969 if (!slab_objcgs(slab) &&
1970 memcg_alloc_slab_cgroups(slab, s, flags, false)) {
1971 obj_cgroup_uncharge(objcg, obj_full_size(s));
1972 continue;
1973 }
1974
1975 off = obj_to_index(s, slab, p[i]);
1976 obj_cgroup_get(objcg);
1977 slab_objcgs(slab)[off] = objcg;
1978 mod_objcg_state(objcg, slab_pgdat(slab),
1979 cache_vmstat_idx(s), obj_full_size(s));
1980 } else {
1981 obj_cgroup_uncharge(objcg, obj_full_size(s));
1982 }
1983 }
1984}
1985
1986static __fastpath_inline
1987void memcg_slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg,
1988 gfp_t flags, size_t size, void **p)
1989{
1990 if (likely(!memcg_kmem_online() || !objcg))
1991 return;
1992
1993 return __memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
1994}
1995
1996static void __memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
1997 void **p, int objects,
1998 struct obj_cgroup **objcgs)
1999{
2000 for (int i = 0; i < objects; i++) {
2001 struct obj_cgroup *objcg;
2002 unsigned int off;
2003
2004 off = obj_to_index(s, slab, p[i]);
2005 objcg = objcgs[off];
2006 if (!objcg)
2007 continue;
2008
2009 objcgs[off] = NULL;
2010 obj_cgroup_uncharge(objcg, obj_full_size(s));
2011 mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s),
2012 -obj_full_size(s));
2013 obj_cgroup_put(objcg);
2014 }
2015}
2016
2017static __fastpath_inline
2018void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, void **p,
2019 int objects)
2020{
2021 struct obj_cgroup **objcgs;
2022
2023 if (!memcg_kmem_online())
2024 return;
2025
2026 objcgs = slab_objcgs(slab);
2027 if (likely(!objcgs))
2028 return;
2029
2030 __memcg_slab_free_hook(s, slab, p, objects, objcgs);
2031}
2032
2033static inline
2034void memcg_slab_alloc_error_hook(struct kmem_cache *s, int objects,
2035 struct obj_cgroup *objcg)
2036{
2037 if (objcg)
2038 obj_cgroup_uncharge(objcg, objects * obj_full_size(s));
2039}
2040#else /* CONFIG_MEMCG_KMEM */
2041static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr)
2042{
2043 return NULL;
2044}
2045
2046static inline void memcg_free_slab_cgroups(struct slab *slab)
2047{
2048}
2049
2050static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s,
2051 struct list_lru *lru,
2052 struct obj_cgroup **objcgp,
2053 size_t objects, gfp_t flags)
2054{
2055 return true;
2056}
2057
2058static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s,
2059 struct obj_cgroup *objcg,
2060 gfp_t flags, size_t size,
2061 void **p)
2062{
2063}
2064
2065static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab,
2066 void **p, int objects)
2067{
2068}
2069
2070static inline
2071void memcg_slab_alloc_error_hook(struct kmem_cache *s, int objects,
2072 struct obj_cgroup *objcg)
2073{
2074}
2075#endif /* CONFIG_MEMCG_KMEM */
2076
2077/*
2078 * Hooks for other subsystems that check memory allocations. In a typical
2079 * production configuration these hooks all should produce no code at all.
2080 *
2081 * Returns true if freeing of the object can proceed, false if its reuse
2082 * was delayed by KASAN quarantine, or it was returned to KFENCE.
2083 */
2084static __always_inline
2085bool slab_free_hook(struct kmem_cache *s, void *x, bool init)
2086{
2087 kmemleak_free_recursive(x, s->flags);
2088 kmsan_slab_free(s, x);
2089
2090 debug_check_no_locks_freed(x, s->object_size);
2091
2092 if (!(s->flags & SLAB_DEBUG_OBJECTS))
2093 debug_check_no_obj_freed(x, s->object_size);
2094
2095 /* Use KCSAN to help debug racy use-after-free. */
2096 if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
2097 __kcsan_check_access(x, s->object_size,
2098 KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
2099
2100 if (kfence_free(x))
2101 return false;
2102
2103 /*
2104 * As memory initialization might be integrated into KASAN,
2105 * kasan_slab_free and initialization memset's must be
2106 * kept together to avoid discrepancies in behavior.
2107 *
2108 * The initialization memset's clear the object and the metadata,
2109 * but don't touch the SLAB redzone.
2110 */
2111 if (unlikely(init)) {
2112 int rsize;
2113
2114 if (!kasan_has_integrated_init())
2115 memset(kasan_reset_tag(x), 0, s->object_size);
2116 rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
2117 memset((char *)kasan_reset_tag(x) + s->inuse, 0,
2118 s->size - s->inuse - rsize);
2119 }
2120 /* KASAN might put x into memory quarantine, delaying its reuse. */
2121 return !kasan_slab_free(s, x, init);
2122}
2123
2124static inline bool slab_free_freelist_hook(struct kmem_cache *s,
2125 void **head, void **tail,
2126 int *cnt)
2127{
2128
2129 void *object;
2130 void *next = *head;
2131 void *old_tail = *tail;
2132 bool init;
2133
2134 if (is_kfence_address(next)) {
2135 slab_free_hook(s, next, false);
2136 return false;
2137 }
2138
2139 /* Head and tail of the reconstructed freelist */
2140 *head = NULL;
2141 *tail = NULL;
2142
2143 init = slab_want_init_on_free(s);
2144
2145 do {
2146 object = next;
2147 next = get_freepointer(s, object);
2148
2149 /* If object's reuse doesn't have to be delayed */
2150 if (likely(slab_free_hook(s, object, init))) {
2151 /* Move object to the new freelist */
2152 set_freepointer(s, object, *head);
2153 *head = object;
2154 if (!*tail)
2155 *tail = object;
2156 } else {
2157 /*
2158 * Adjust the reconstructed freelist depth
2159 * accordingly if object's reuse is delayed.
2160 */
2161 --(*cnt);
2162 }
2163 } while (object != old_tail);
2164
2165 return *head != NULL;
2166}
2167
2168static void *setup_object(struct kmem_cache *s, void *object)
2169{
2170 setup_object_debug(s, object);
2171 object = kasan_init_slab_obj(s, object);
2172 if (unlikely(s->ctor)) {
2173 kasan_unpoison_new_object(s, object);
2174 s->ctor(object);
2175 kasan_poison_new_object(s, object);
2176 }
2177 return object;
2178}
2179
2180/*
2181 * Slab allocation and freeing
2182 */
2183static inline struct slab *alloc_slab_page(gfp_t flags, int node,
2184 struct kmem_cache_order_objects oo)
2185{
2186 struct folio *folio;
2187 struct slab *slab;
2188 unsigned int order = oo_order(oo);
2189
2190 folio = (struct folio *)alloc_pages_node(node, flags, order);
2191 if (!folio)
2192 return NULL;
2193
2194 slab = folio_slab(folio);
2195 __folio_set_slab(folio);
2196 /* Make the flag visible before any changes to folio->mapping */
2197 smp_wmb();
2198 if (folio_is_pfmemalloc(folio))
2199 slab_set_pfmemalloc(slab);
2200
2201 return slab;
2202}
2203
2204#ifdef CONFIG_SLAB_FREELIST_RANDOM
2205/* Pre-initialize the random sequence cache */
2206static int init_cache_random_seq(struct kmem_cache *s)
2207{
2208 unsigned int count = oo_objects(s->oo);
2209 int err;
2210
2211 /* Bailout if already initialised */
2212 if (s->random_seq)
2213 return 0;
2214
2215 err = cache_random_seq_create(s, count, GFP_KERNEL);
2216 if (err) {
2217 pr_err("SLUB: Unable to initialize free list for %s\n",
2218 s->name);
2219 return err;
2220 }
2221
2222 /* Transform to an offset on the set of pages */
2223 if (s->random_seq) {
2224 unsigned int i;
2225
2226 for (i = 0; i < count; i++)
2227 s->random_seq[i] *= s->size;
2228 }
2229 return 0;
2230}
2231
2232/* Initialize each random sequence freelist per cache */
2233static void __init init_freelist_randomization(void)
2234{
2235 struct kmem_cache *s;
2236
2237 mutex_lock(&slab_mutex);
2238
2239 list_for_each_entry(s, &slab_caches, list)
2240 init_cache_random_seq(s);
2241
2242 mutex_unlock(&slab_mutex);
2243}
2244
2245/* Get the next entry on the pre-computed freelist randomized */
2246static void *next_freelist_entry(struct kmem_cache *s, struct slab *slab,
2247 unsigned long *pos, void *start,
2248 unsigned long page_limit,
2249 unsigned long freelist_count)
2250{
2251 unsigned int idx;
2252
2253 /*
2254 * If the target page allocation failed, the number of objects on the
2255 * page might be smaller than the usual size defined by the cache.
2256 */
2257 do {
2258 idx = s->random_seq[*pos];
2259 *pos += 1;
2260 if (*pos >= freelist_count)
2261 *pos = 0;
2262 } while (unlikely(idx >= page_limit));
2263
2264 return (char *)start + idx;
2265}
2266
2267/* Shuffle the single linked freelist based on a random pre-computed sequence */
2268static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
2269{
2270 void *start;
2271 void *cur;
2272 void *next;
2273 unsigned long idx, pos, page_limit, freelist_count;
2274
2275 if (slab->objects < 2 || !s->random_seq)
2276 return false;
2277
2278 freelist_count = oo_objects(s->oo);
2279 pos = get_random_u32_below(freelist_count);
2280
2281 page_limit = slab->objects * s->size;
2282 start = fixup_red_left(s, slab_address(slab));
2283
2284 /* First entry is used as the base of the freelist */
2285 cur = next_freelist_entry(s, slab, &pos, start, page_limit,
2286 freelist_count);
2287 cur = setup_object(s, cur);
2288 slab->freelist = cur;
2289
2290 for (idx = 1; idx < slab->objects; idx++) {
2291 next = next_freelist_entry(s, slab, &pos, start, page_limit,
2292 freelist_count);
2293 next = setup_object(s, next);
2294 set_freepointer(s, cur, next);
2295 cur = next;
2296 }
2297 set_freepointer(s, cur, NULL);
2298
2299 return true;
2300}
2301#else
2302static inline int init_cache_random_seq(struct kmem_cache *s)
2303{
2304 return 0;
2305}
2306static inline void init_freelist_randomization(void) { }
2307static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
2308{
2309 return false;
2310}
2311#endif /* CONFIG_SLAB_FREELIST_RANDOM */
2312
2313static __always_inline void account_slab(struct slab *slab, int order,
2314 struct kmem_cache *s, gfp_t gfp)
2315{
2316 if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT))
2317 memcg_alloc_slab_cgroups(slab, s, gfp, true);
2318
2319 mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
2320 PAGE_SIZE << order);
2321}
2322
2323static __always_inline void unaccount_slab(struct slab *slab, int order,
2324 struct kmem_cache *s)
2325{
2326 if (memcg_kmem_online())
2327 memcg_free_slab_cgroups(slab);
2328
2329 mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s),
2330 -(PAGE_SIZE << order));
2331}
2332
2333static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
2334{
2335 struct slab *slab;
2336 struct kmem_cache_order_objects oo = s->oo;
2337 gfp_t alloc_gfp;
2338 void *start, *p, *next;
2339 int idx;
2340 bool shuffle;
2341
2342 flags &= gfp_allowed_mask;
2343
2344 flags |= s->allocflags;
2345
2346 /*
2347 * Let the initial higher-order allocation fail under memory pressure
2348 * so we fall-back to the minimum order allocation.
2349 */
2350 alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
2351 if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
2352 alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
2353
2354 slab = alloc_slab_page(alloc_gfp, node, oo);
2355 if (unlikely(!slab)) {
2356 oo = s->min;
2357 alloc_gfp = flags;
2358 /*
2359 * Allocation may have failed due to fragmentation.
2360 * Try a lower order alloc if possible
2361 */
2362 slab = alloc_slab_page(alloc_gfp, node, oo);
2363 if (unlikely(!slab))
2364 return NULL;
2365 stat(s, ORDER_FALLBACK);
2366 }
2367
2368 slab->objects = oo_objects(oo);
2369 slab->inuse = 0;
2370 slab->frozen = 0;
2371
2372 account_slab(slab, oo_order(oo), s, flags);
2373
2374 slab->slab_cache = s;
2375
2376 kasan_poison_slab(slab);
2377
2378 start = slab_address(slab);
2379
2380 setup_slab_debug(s, slab, start);
2381
2382 shuffle = shuffle_freelist(s, slab);
2383
2384 if (!shuffle) {
2385 start = fixup_red_left(s, start);
2386 start = setup_object(s, start);
2387 slab->freelist = start;
2388 for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
2389 next = p + s->size;
2390 next = setup_object(s, next);
2391 set_freepointer(s, p, next);
2392 p = next;
2393 }
2394 set_freepointer(s, p, NULL);
2395 }
2396
2397 return slab;
2398}
2399
2400static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
2401{
2402 if (unlikely(flags & GFP_SLAB_BUG_MASK))
2403 flags = kmalloc_fix_flags(flags);
2404
2405 WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
2406
2407 return allocate_slab(s,
2408 flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
2409}
2410
2411static void __free_slab(struct kmem_cache *s, struct slab *slab)
2412{
2413 struct folio *folio = slab_folio(slab);
2414 int order = folio_order(folio);
2415 int pages = 1 << order;
2416
2417 __slab_clear_pfmemalloc(slab);
2418 folio->mapping = NULL;
2419 /* Make the mapping reset visible before clearing the flag */
2420 smp_wmb();
2421 __folio_clear_slab(folio);
2422 mm_account_reclaimed_pages(pages);
2423 unaccount_slab(slab, order, s);
2424 __free_pages(&folio->page, order);
2425}
2426
2427static void rcu_free_slab(struct rcu_head *h)
2428{
2429 struct slab *slab = container_of(h, struct slab, rcu_head);
2430
2431 __free_slab(slab->slab_cache, slab);
2432}
2433
2434static void free_slab(struct kmem_cache *s, struct slab *slab)
2435{
2436 if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
2437 void *p;
2438
2439 slab_pad_check(s, slab);
2440 for_each_object(p, s, slab_address(slab), slab->objects)
2441 check_object(s, slab, p, SLUB_RED_INACTIVE);
2442 }
2443
2444 if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU))
2445 call_rcu(&slab->rcu_head, rcu_free_slab);
2446 else
2447 __free_slab(s, slab);
2448}
2449
2450static void discard_slab(struct kmem_cache *s, struct slab *slab)
2451{
2452 dec_slabs_node(s, slab_nid(slab), slab->objects);
2453 free_slab(s, slab);
2454}
2455
2456/*
2457 * SLUB reuses PG_workingset bit to keep track of whether it's on
2458 * the per-node partial list.
2459 */
2460static inline bool slab_test_node_partial(const struct slab *slab)
2461{
2462 return folio_test_workingset((struct folio *)slab_folio(slab));
2463}
2464
2465static inline void slab_set_node_partial(struct slab *slab)
2466{
2467 set_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
2468}
2469
2470static inline void slab_clear_node_partial(struct slab *slab)
2471{
2472 clear_bit(PG_workingset, folio_flags(slab_folio(slab), 0));
2473}
2474
2475/*
2476 * Management of partially allocated slabs.
2477 */
2478static inline void
2479__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
2480{
2481 n->nr_partial++;
2482 if (tail == DEACTIVATE_TO_TAIL)
2483 list_add_tail(&slab->slab_list, &n->partial);
2484 else
2485 list_add(&slab->slab_list, &n->partial);
2486 slab_set_node_partial(slab);
2487}
2488
2489static inline void add_partial(struct kmem_cache_node *n,
2490 struct slab *slab, int tail)
2491{
2492 lockdep_assert_held(&n->list_lock);
2493 __add_partial(n, slab, tail);
2494}
2495
2496static inline void remove_partial(struct kmem_cache_node *n,
2497 struct slab *slab)
2498{
2499 lockdep_assert_held(&n->list_lock);
2500 list_del(&slab->slab_list);
2501 slab_clear_node_partial(slab);
2502 n->nr_partial--;
2503}
2504
2505/*
2506 * Called only for kmem_cache_debug() caches instead of remove_partial(), with a
2507 * slab from the n->partial list. Remove only a single object from the slab, do
2508 * the alloc_debug_processing() checks and leave the slab on the list, or move
2509 * it to full list if it was the last free object.
2510 */
2511static void *alloc_single_from_partial(struct kmem_cache *s,
2512 struct kmem_cache_node *n, struct slab *slab, int orig_size)
2513{
2514 void *object;
2515
2516 lockdep_assert_held(&n->list_lock);
2517
2518 object = slab->freelist;
2519 slab->freelist = get_freepointer(s, object);
2520 slab->inuse++;
2521
2522 if (!alloc_debug_processing(s, slab, object, orig_size)) {
2523 remove_partial(n, slab);
2524 return NULL;
2525 }
2526
2527 if (slab->inuse == slab->objects) {
2528 remove_partial(n, slab);
2529 add_full(s, n, slab);
2530 }
2531
2532 return object;
2533}
2534
2535/*
2536 * Called only for kmem_cache_debug() caches to allocate from a freshly
2537 * allocated slab. Allocate a single object instead of whole freelist
2538 * and put the slab to the partial (or full) list.
2539 */
2540static void *alloc_single_from_new_slab(struct kmem_cache *s,
2541 struct slab *slab, int orig_size)
2542{
2543 int nid = slab_nid(slab);
2544 struct kmem_cache_node *n = get_node(s, nid);
2545 unsigned long flags;
2546 void *object;
2547
2548
2549 object = slab->freelist;
2550 slab->freelist = get_freepointer(s, object);
2551 slab->inuse = 1;
2552
2553 if (!alloc_debug_processing(s, slab, object, orig_size))
2554 /*
2555 * It's not really expected that this would fail on a
2556 * freshly allocated slab, but a concurrent memory
2557 * corruption in theory could cause that.
2558 */
2559 return NULL;
2560
2561 spin_lock_irqsave(&n->list_lock, flags);
2562
2563 if (slab->inuse == slab->objects)
2564 add_full(s, n, slab);
2565 else
2566 add_partial(n, slab, DEACTIVATE_TO_HEAD);
2567
2568 inc_slabs_node(s, nid, slab->objects);
2569 spin_unlock_irqrestore(&n->list_lock, flags);
2570
2571 return object;
2572}
2573
2574#ifdef CONFIG_SLUB_CPU_PARTIAL
2575static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
2576#else
2577static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
2578 int drain) { }
2579#endif
2580static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
2581
2582/*
2583 * Try to allocate a partial slab from a specific node.
2584 */
2585static struct slab *get_partial_node(struct kmem_cache *s,
2586 struct kmem_cache_node *n,
2587 struct partial_context *pc)
2588{
2589 struct slab *slab, *slab2, *partial = NULL;
2590 unsigned long flags;
2591 unsigned int partial_slabs = 0;
2592
2593 /*
2594 * Racy check. If we mistakenly see no partial slabs then we
2595 * just allocate an empty slab. If we mistakenly try to get a
2596 * partial slab and there is none available then get_partial()
2597 * will return NULL.
2598 */
2599 if (!n || !n->nr_partial)
2600 return NULL;
2601
2602 spin_lock_irqsave(&n->list_lock, flags);
2603 list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
2604 if (!pfmemalloc_match(slab, pc->flags))
2605 continue;
2606
2607 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
2608 void *object = alloc_single_from_partial(s, n, slab,
2609 pc->orig_size);
2610 if (object) {
2611 partial = slab;
2612 pc->object = object;
2613 break;
2614 }
2615 continue;
2616 }
2617
2618 remove_partial(n, slab);
2619
2620 if (!partial) {
2621 partial = slab;
2622 stat(s, ALLOC_FROM_PARTIAL);
2623 } else {
2624 put_cpu_partial(s, slab, 0);
2625 stat(s, CPU_PARTIAL_NODE);
2626 partial_slabs++;
2627 }
2628#ifdef CONFIG_SLUB_CPU_PARTIAL
2629 if (!kmem_cache_has_cpu_partial(s)
2630 || partial_slabs > s->cpu_partial_slabs / 2)
2631 break;
2632#else
2633 break;
2634#endif
2635
2636 }
2637 spin_unlock_irqrestore(&n->list_lock, flags);
2638 return partial;
2639}
2640
2641/*
2642 * Get a slab from somewhere. Search in increasing NUMA distances.
2643 */
2644static struct slab *get_any_partial(struct kmem_cache *s,
2645 struct partial_context *pc)
2646{
2647#ifdef CONFIG_NUMA
2648 struct zonelist *zonelist;
2649 struct zoneref *z;
2650 struct zone *zone;
2651 enum zone_type highest_zoneidx = gfp_zone(pc->flags);
2652 struct slab *slab;
2653 unsigned int cpuset_mems_cookie;
2654
2655 /*
2656 * The defrag ratio allows a configuration of the tradeoffs between
2657 * inter node defragmentation and node local allocations. A lower
2658 * defrag_ratio increases the tendency to do local allocations
2659 * instead of attempting to obtain partial slabs from other nodes.
2660 *
2661 * If the defrag_ratio is set to 0 then kmalloc() always
2662 * returns node local objects. If the ratio is higher then kmalloc()
2663 * may return off node objects because partial slabs are obtained
2664 * from other nodes and filled up.
2665 *
2666 * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
2667 * (which makes defrag_ratio = 1000) then every (well almost)
2668 * allocation will first attempt to defrag slab caches on other nodes.
2669 * This means scanning over all nodes to look for partial slabs which
2670 * may be expensive if we do it every time we are trying to find a slab
2671 * with available objects.
2672 */
2673 if (!s->remote_node_defrag_ratio ||
2674 get_cycles() % 1024 > s->remote_node_defrag_ratio)
2675 return NULL;
2676
2677 do {
2678 cpuset_mems_cookie = read_mems_allowed_begin();
2679 zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
2680 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
2681 struct kmem_cache_node *n;
2682
2683 n = get_node(s, zone_to_nid(zone));
2684
2685 if (n && cpuset_zone_allowed(zone, pc->flags) &&
2686 n->nr_partial > s->min_partial) {
2687 slab = get_partial_node(s, n, pc);
2688 if (slab) {
2689 /*
2690 * Don't check read_mems_allowed_retry()
2691 * here - if mems_allowed was updated in
2692 * parallel, that was a harmless race
2693 * between allocation and the cpuset
2694 * update
2695 */
2696 return slab;
2697 }
2698 }
2699 }
2700 } while (read_mems_allowed_retry(cpuset_mems_cookie));
2701#endif /* CONFIG_NUMA */
2702 return NULL;
2703}
2704
2705/*
2706 * Get a partial slab, lock it and return it.
2707 */
2708static struct slab *get_partial(struct kmem_cache *s, int node,
2709 struct partial_context *pc)
2710{
2711 struct slab *slab;
2712 int searchnode = node;
2713
2714 if (node == NUMA_NO_NODE)
2715 searchnode = numa_mem_id();
2716
2717 slab = get_partial_node(s, get_node(s, searchnode), pc);
2718 if (slab || node != NUMA_NO_NODE)
2719 return slab;
2720
2721 return get_any_partial(s, pc);
2722}
2723
2724#ifndef CONFIG_SLUB_TINY
2725
2726#ifdef CONFIG_PREEMPTION
2727/*
2728 * Calculate the next globally unique transaction for disambiguation
2729 * during cmpxchg. The transactions start with the cpu number and are then
2730 * incremented by CONFIG_NR_CPUS.
2731 */
2732#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
2733#else
2734/*
2735 * No preemption supported therefore also no need to check for
2736 * different cpus.
2737 */
2738#define TID_STEP 1
2739#endif /* CONFIG_PREEMPTION */
2740
2741static inline unsigned long next_tid(unsigned long tid)
2742{
2743 return tid + TID_STEP;
2744}
2745
2746#ifdef SLUB_DEBUG_CMPXCHG
2747static inline unsigned int tid_to_cpu(unsigned long tid)
2748{
2749 return tid % TID_STEP;
2750}
2751
2752static inline unsigned long tid_to_event(unsigned long tid)
2753{
2754 return tid / TID_STEP;
2755}
2756#endif
2757
2758static inline unsigned int init_tid(int cpu)
2759{
2760 return cpu;
2761}
2762
2763static inline void note_cmpxchg_failure(const char *n,
2764 const struct kmem_cache *s, unsigned long tid)
2765{
2766#ifdef SLUB_DEBUG_CMPXCHG
2767 unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
2768
2769 pr_info("%s %s: cmpxchg redo ", n, s->name);
2770
2771#ifdef CONFIG_PREEMPTION
2772 if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
2773 pr_warn("due to cpu change %d -> %d\n",
2774 tid_to_cpu(tid), tid_to_cpu(actual_tid));
2775 else
2776#endif
2777 if (tid_to_event(tid) != tid_to_event(actual_tid))
2778 pr_warn("due to cpu running other code. Event %ld->%ld\n",
2779 tid_to_event(tid), tid_to_event(actual_tid));
2780 else
2781 pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
2782 actual_tid, tid, next_tid(tid));
2783#endif
2784 stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
2785}
2786
2787static void init_kmem_cache_cpus(struct kmem_cache *s)
2788{
2789 int cpu;
2790 struct kmem_cache_cpu *c;
2791
2792 for_each_possible_cpu(cpu) {
2793 c = per_cpu_ptr(s->cpu_slab, cpu);
2794 local_lock_init(&c->lock);
2795 c->tid = init_tid(cpu);
2796 }
2797}
2798
2799/*
2800 * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
2801 * unfreezes the slabs and puts it on the proper list.
2802 * Assumes the slab has been already safely taken away from kmem_cache_cpu
2803 * by the caller.
2804 */
2805static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
2806 void *freelist)
2807{
2808 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
2809 int free_delta = 0;
2810 void *nextfree, *freelist_iter, *freelist_tail;
2811 int tail = DEACTIVATE_TO_HEAD;
2812 unsigned long flags = 0;
2813 struct slab new;
2814 struct slab old;
2815
2816 if (slab->freelist) {
2817 stat(s, DEACTIVATE_REMOTE_FREES);
2818 tail = DEACTIVATE_TO_TAIL;
2819 }
2820
2821 /*
2822 * Stage one: Count the objects on cpu's freelist as free_delta and
2823 * remember the last object in freelist_tail for later splicing.
2824 */
2825 freelist_tail = NULL;
2826 freelist_iter = freelist;
2827 while (freelist_iter) {
2828 nextfree = get_freepointer(s, freelist_iter);
2829
2830 /*
2831 * If 'nextfree' is invalid, it is possible that the object at
2832 * 'freelist_iter' is already corrupted. So isolate all objects
2833 * starting at 'freelist_iter' by skipping them.
2834 */
2835 if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
2836 break;
2837
2838 freelist_tail = freelist_iter;
2839 free_delta++;
2840
2841 freelist_iter = nextfree;
2842 }
2843
2844 /*
2845 * Stage two: Unfreeze the slab while splicing the per-cpu
2846 * freelist to the head of slab's freelist.
2847 */
2848 do {
2849 old.freelist = READ_ONCE(slab->freelist);
2850 old.counters = READ_ONCE(slab->counters);
2851 VM_BUG_ON(!old.frozen);
2852
2853 /* Determine target state of the slab */
2854 new.counters = old.counters;
2855 new.frozen = 0;
2856 if (freelist_tail) {
2857 new.inuse -= free_delta;
2858 set_freepointer(s, freelist_tail, old.freelist);
2859 new.freelist = freelist;
2860 } else {
2861 new.freelist = old.freelist;
2862 }
2863 } while (!slab_update_freelist(s, slab,
2864 old.freelist, old.counters,
2865 new.freelist, new.counters,
2866 "unfreezing slab"));
2867
2868 /*
2869 * Stage three: Manipulate the slab list based on the updated state.
2870 */
2871 if (!new.inuse && n->nr_partial >= s->min_partial) {
2872 stat(s, DEACTIVATE_EMPTY);
2873 discard_slab(s, slab);
2874 stat(s, FREE_SLAB);
2875 } else if (new.freelist) {
2876 spin_lock_irqsave(&n->list_lock, flags);
2877 add_partial(n, slab, tail);
2878 spin_unlock_irqrestore(&n->list_lock, flags);
2879 stat(s, tail);
2880 } else {
2881 stat(s, DEACTIVATE_FULL);
2882 }
2883}
2884
2885#ifdef CONFIG_SLUB_CPU_PARTIAL
2886static void __put_partials(struct kmem_cache *s, struct slab *partial_slab)
2887{
2888 struct kmem_cache_node *n = NULL, *n2 = NULL;
2889 struct slab *slab, *slab_to_discard = NULL;
2890 unsigned long flags = 0;
2891
2892 while (partial_slab) {
2893 slab = partial_slab;
2894 partial_slab = slab->next;
2895
2896 n2 = get_node(s, slab_nid(slab));
2897 if (n != n2) {
2898 if (n)
2899 spin_unlock_irqrestore(&n->list_lock, flags);
2900
2901 n = n2;
2902 spin_lock_irqsave(&n->list_lock, flags);
2903 }
2904
2905 if (unlikely(!slab->inuse && n->nr_partial >= s->min_partial)) {
2906 slab->next = slab_to_discard;
2907 slab_to_discard = slab;
2908 } else {
2909 add_partial(n, slab, DEACTIVATE_TO_TAIL);
2910 stat(s, FREE_ADD_PARTIAL);
2911 }
2912 }
2913
2914 if (n)
2915 spin_unlock_irqrestore(&n->list_lock, flags);
2916
2917 while (slab_to_discard) {
2918 slab = slab_to_discard;
2919 slab_to_discard = slab_to_discard->next;
2920
2921 stat(s, DEACTIVATE_EMPTY);
2922 discard_slab(s, slab);
2923 stat(s, FREE_SLAB);
2924 }
2925}
2926
2927/*
2928 * Put all the cpu partial slabs to the node partial list.
2929 */
2930static void put_partials(struct kmem_cache *s)
2931{
2932 struct slab *partial_slab;
2933 unsigned long flags;
2934
2935 local_lock_irqsave(&s->cpu_slab->lock, flags);
2936 partial_slab = this_cpu_read(s->cpu_slab->partial);
2937 this_cpu_write(s->cpu_slab->partial, NULL);
2938 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2939
2940 if (partial_slab)
2941 __put_partials(s, partial_slab);
2942}
2943
2944static void put_partials_cpu(struct kmem_cache *s,
2945 struct kmem_cache_cpu *c)
2946{
2947 struct slab *partial_slab;
2948
2949 partial_slab = slub_percpu_partial(c);
2950 c->partial = NULL;
2951
2952 if (partial_slab)
2953 __put_partials(s, partial_slab);
2954}
2955
2956/*
2957 * Put a slab into a partial slab slot if available.
2958 *
2959 * If we did not find a slot then simply move all the partials to the
2960 * per node partial list.
2961 */
2962static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
2963{
2964 struct slab *oldslab;
2965 struct slab *slab_to_put = NULL;
2966 unsigned long flags;
2967 int slabs = 0;
2968
2969 local_lock_irqsave(&s->cpu_slab->lock, flags);
2970
2971 oldslab = this_cpu_read(s->cpu_slab->partial);
2972
2973 if (oldslab) {
2974 if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
2975 /*
2976 * Partial array is full. Move the existing set to the
2977 * per node partial list. Postpone the actual unfreezing
2978 * outside of the critical section.
2979 */
2980 slab_to_put = oldslab;
2981 oldslab = NULL;
2982 } else {
2983 slabs = oldslab->slabs;
2984 }
2985 }
2986
2987 slabs++;
2988
2989 slab->slabs = slabs;
2990 slab->next = oldslab;
2991
2992 this_cpu_write(s->cpu_slab->partial, slab);
2993
2994 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
2995
2996 if (slab_to_put) {
2997 __put_partials(s, slab_to_put);
2998 stat(s, CPU_PARTIAL_DRAIN);
2999 }
3000}
3001
3002#else /* CONFIG_SLUB_CPU_PARTIAL */
3003
3004static inline void put_partials(struct kmem_cache *s) { }
3005static inline void put_partials_cpu(struct kmem_cache *s,
3006 struct kmem_cache_cpu *c) { }
3007
3008#endif /* CONFIG_SLUB_CPU_PARTIAL */
3009
3010static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
3011{
3012 unsigned long flags;
3013 struct slab *slab;
3014 void *freelist;
3015
3016 local_lock_irqsave(&s->cpu_slab->lock, flags);
3017
3018 slab = c->slab;
3019 freelist = c->freelist;
3020
3021 c->slab = NULL;
3022 c->freelist = NULL;
3023 c->tid = next_tid(c->tid);
3024
3025 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3026
3027 if (slab) {
3028 deactivate_slab(s, slab, freelist);
3029 stat(s, CPUSLAB_FLUSH);
3030 }
3031}
3032
3033static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
3034{
3035 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
3036 void *freelist = c->freelist;
3037 struct slab *slab = c->slab;
3038
3039 c->slab = NULL;
3040 c->freelist = NULL;
3041 c->tid = next_tid(c->tid);
3042
3043 if (slab) {
3044 deactivate_slab(s, slab, freelist);
3045 stat(s, CPUSLAB_FLUSH);
3046 }
3047
3048 put_partials_cpu(s, c);
3049}
3050
3051struct slub_flush_work {
3052 struct work_struct work;
3053 struct kmem_cache *s;
3054 bool skip;
3055};
3056
3057/*
3058 * Flush cpu slab.
3059 *
3060 * Called from CPU work handler with migration disabled.
3061 */
3062static void flush_cpu_slab(struct work_struct *w)
3063{
3064 struct kmem_cache *s;
3065 struct kmem_cache_cpu *c;
3066 struct slub_flush_work *sfw;
3067
3068 sfw = container_of(w, struct slub_flush_work, work);
3069
3070 s = sfw->s;
3071 c = this_cpu_ptr(s->cpu_slab);
3072
3073 if (c->slab)
3074 flush_slab(s, c);
3075
3076 put_partials(s);
3077}
3078
3079static bool has_cpu_slab(int cpu, struct kmem_cache *s)
3080{
3081 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
3082
3083 return c->slab || slub_percpu_partial(c);
3084}
3085
3086static DEFINE_MUTEX(flush_lock);
3087static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
3088
3089static void flush_all_cpus_locked(struct kmem_cache *s)
3090{
3091 struct slub_flush_work *sfw;
3092 unsigned int cpu;
3093
3094 lockdep_assert_cpus_held();
3095 mutex_lock(&flush_lock);
3096
3097 for_each_online_cpu(cpu) {
3098 sfw = &per_cpu(slub_flush, cpu);
3099 if (!has_cpu_slab(cpu, s)) {
3100 sfw->skip = true;
3101 continue;
3102 }
3103 INIT_WORK(&sfw->work, flush_cpu_slab);
3104 sfw->skip = false;
3105 sfw->s = s;
3106 queue_work_on(cpu, flushwq, &sfw->work);
3107 }
3108
3109 for_each_online_cpu(cpu) {
3110 sfw = &per_cpu(slub_flush, cpu);
3111 if (sfw->skip)
3112 continue;
3113 flush_work(&sfw->work);
3114 }
3115
3116 mutex_unlock(&flush_lock);
3117}
3118
3119static void flush_all(struct kmem_cache *s)
3120{
3121 cpus_read_lock();
3122 flush_all_cpus_locked(s);
3123 cpus_read_unlock();
3124}
3125
3126/*
3127 * Use the cpu notifier to insure that the cpu slabs are flushed when
3128 * necessary.
3129 */
3130static int slub_cpu_dead(unsigned int cpu)
3131{
3132 struct kmem_cache *s;
3133
3134 mutex_lock(&slab_mutex);
3135 list_for_each_entry(s, &slab_caches, list)
3136 __flush_cpu_slab(s, cpu);
3137 mutex_unlock(&slab_mutex);
3138 return 0;
3139}
3140
3141#else /* CONFIG_SLUB_TINY */
3142static inline void flush_all_cpus_locked(struct kmem_cache *s) { }
3143static inline void flush_all(struct kmem_cache *s) { }
3144static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) { }
3145static inline int slub_cpu_dead(unsigned int cpu) { return 0; }
3146#endif /* CONFIG_SLUB_TINY */
3147
3148/*
3149 * Check if the objects in a per cpu structure fit numa
3150 * locality expectations.
3151 */
3152static inline int node_match(struct slab *slab, int node)
3153{
3154#ifdef CONFIG_NUMA
3155 if (node != NUMA_NO_NODE && slab_nid(slab) != node)
3156 return 0;
3157#endif
3158 return 1;
3159}
3160
3161#ifdef CONFIG_SLUB_DEBUG
3162static int count_free(struct slab *slab)
3163{
3164 return slab->objects - slab->inuse;
3165}
3166
3167static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
3168{
3169 return atomic_long_read(&n->total_objects);
3170}
3171
3172/* Supports checking bulk free of a constructed freelist */
3173static inline bool free_debug_processing(struct kmem_cache *s,
3174 struct slab *slab, void *head, void *tail, int *bulk_cnt,
3175 unsigned long addr, depot_stack_handle_t handle)
3176{
3177 bool checks_ok = false;
3178 void *object = head;
3179 int cnt = 0;
3180
3181 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
3182 if (!check_slab(s, slab))
3183 goto out;
3184 }
3185
3186 if (slab->inuse < *bulk_cnt) {
3187 slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
3188 slab->inuse, *bulk_cnt);
3189 goto out;
3190 }
3191
3192next_object:
3193
3194 if (++cnt > *bulk_cnt)
3195 goto out_cnt;
3196
3197 if (s->flags & SLAB_CONSISTENCY_CHECKS) {
3198 if (!free_consistency_checks(s, slab, object, addr))
3199 goto out;
3200 }
3201
3202 if (s->flags & SLAB_STORE_USER)
3203 set_track_update(s, object, TRACK_FREE, addr, handle);
3204 trace(s, slab, object, 0);
3205 /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
3206 init_object(s, object, SLUB_RED_INACTIVE);
3207
3208 /* Reached end of constructed freelist yet? */
3209 if (object != tail) {
3210 object = get_freepointer(s, object);
3211 goto next_object;
3212 }
3213 checks_ok = true;
3214
3215out_cnt:
3216 if (cnt != *bulk_cnt) {
3217 slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
3218 *bulk_cnt, cnt);
3219 *bulk_cnt = cnt;
3220 }
3221
3222out:
3223
3224 if (!checks_ok)
3225 slab_fix(s, "Object at 0x%p not freed", object);
3226
3227 return checks_ok;
3228}
3229#endif /* CONFIG_SLUB_DEBUG */
3230
3231#if defined(CONFIG_SLUB_DEBUG) || defined(SLAB_SUPPORTS_SYSFS)
3232static unsigned long count_partial(struct kmem_cache_node *n,
3233 int (*get_count)(struct slab *))
3234{
3235 unsigned long flags;
3236 unsigned long x = 0;
3237 struct slab *slab;
3238
3239 spin_lock_irqsave(&n->list_lock, flags);
3240 list_for_each_entry(slab, &n->partial, slab_list)
3241 x += get_count(slab);
3242 spin_unlock_irqrestore(&n->list_lock, flags);
3243 return x;
3244}
3245#endif /* CONFIG_SLUB_DEBUG || SLAB_SUPPORTS_SYSFS */
3246
3247#ifdef CONFIG_SLUB_DEBUG
3248static noinline void
3249slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
3250{
3251 static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
3252 DEFAULT_RATELIMIT_BURST);
3253 int node;
3254 struct kmem_cache_node *n;
3255
3256 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
3257 return;
3258
3259 pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
3260 nid, gfpflags, &gfpflags);
3261 pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
3262 s->name, s->object_size, s->size, oo_order(s->oo),
3263 oo_order(s->min));
3264
3265 if (oo_order(s->min) > get_order(s->object_size))
3266 pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
3267 s->name);
3268
3269 for_each_kmem_cache_node(s, node, n) {
3270 unsigned long nr_slabs;
3271 unsigned long nr_objs;
3272 unsigned long nr_free;
3273
3274 nr_free = count_partial(n, count_free);
3275 nr_slabs = node_nr_slabs(n);
3276 nr_objs = node_nr_objs(n);
3277
3278 pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
3279 node, nr_slabs, nr_objs, nr_free);
3280 }
3281}
3282#else /* CONFIG_SLUB_DEBUG */
3283static inline void
3284slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) { }
3285#endif
3286
3287static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
3288{
3289 if (unlikely(slab_test_pfmemalloc(slab)))
3290 return gfp_pfmemalloc_allowed(gfpflags);
3291
3292 return true;
3293}
3294
3295#ifndef CONFIG_SLUB_TINY
3296static inline bool
3297__update_cpu_freelist_fast(struct kmem_cache *s,
3298 void *freelist_old, void *freelist_new,
3299 unsigned long tid)
3300{
3301 freelist_aba_t old = { .freelist = freelist_old, .counter = tid };
3302 freelist_aba_t new = { .freelist = freelist_new, .counter = next_tid(tid) };
3303
3304 return this_cpu_try_cmpxchg_freelist(s->cpu_slab->freelist_tid.full,
3305 &old.full, new.full);
3306}
3307
3308/*
3309 * Check the slab->freelist and either transfer the freelist to the
3310 * per cpu freelist or deactivate the slab.
3311 *
3312 * The slab is still frozen if the return value is not NULL.
3313 *
3314 * If this function returns NULL then the slab has been unfrozen.
3315 */
3316static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
3317{
3318 struct slab new;
3319 unsigned long counters;
3320 void *freelist;
3321
3322 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3323
3324 do {
3325 freelist = slab->freelist;
3326 counters = slab->counters;
3327
3328 new.counters = counters;
3329 VM_BUG_ON(!new.frozen);
3330
3331 new.inuse = slab->objects;
3332 new.frozen = freelist != NULL;
3333
3334 } while (!__slab_update_freelist(s, slab,
3335 freelist, counters,
3336 NULL, new.counters,
3337 "get_freelist"));
3338
3339 return freelist;
3340}
3341
3342/*
3343 * Freeze the partial slab and return the pointer to the freelist.
3344 */
3345static inline void *freeze_slab(struct kmem_cache *s, struct slab *slab)
3346{
3347 struct slab new;
3348 unsigned long counters;
3349 void *freelist;
3350
3351 do {
3352 freelist = slab->freelist;
3353 counters = slab->counters;
3354
3355 new.counters = counters;
3356 VM_BUG_ON(new.frozen);
3357
3358 new.inuse = slab->objects;
3359 new.frozen = 1;
3360
3361 } while (!slab_update_freelist(s, slab,
3362 freelist, counters,
3363 NULL, new.counters,
3364 "freeze_slab"));
3365
3366 return freelist;
3367}
3368
3369/*
3370 * Slow path. The lockless freelist is empty or we need to perform
3371 * debugging duties.
3372 *
3373 * Processing is still very fast if new objects have been freed to the
3374 * regular freelist. In that case we simply take over the regular freelist
3375 * as the lockless freelist and zap the regular freelist.
3376 *
3377 * If that is not working then we fall back to the partial lists. We take the
3378 * first element of the freelist as the object to allocate now and move the
3379 * rest of the freelist to the lockless freelist.
3380 *
3381 * And if we were unable to get a new slab from the partial slab lists then
3382 * we need to allocate a new slab. This is the slowest path since it involves
3383 * a call to the page allocator and the setup of a new slab.
3384 *
3385 * Version of __slab_alloc to use when we know that preemption is
3386 * already disabled (which is the case for bulk allocation).
3387 */
3388static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3389 unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3390{
3391 void *freelist;
3392 struct slab *slab;
3393 unsigned long flags;
3394 struct partial_context pc;
3395
3396 stat(s, ALLOC_SLOWPATH);
3397
3398reread_slab:
3399
3400 slab = READ_ONCE(c->slab);
3401 if (!slab) {
3402 /*
3403 * if the node is not online or has no normal memory, just
3404 * ignore the node constraint
3405 */
3406 if (unlikely(node != NUMA_NO_NODE &&
3407 !node_isset(node, slab_nodes)))
3408 node = NUMA_NO_NODE;
3409 goto new_slab;
3410 }
3411
3412 if (unlikely(!node_match(slab, node))) {
3413 /*
3414 * same as above but node_match() being false already
3415 * implies node != NUMA_NO_NODE
3416 */
3417 if (!node_isset(node, slab_nodes)) {
3418 node = NUMA_NO_NODE;
3419 } else {
3420 stat(s, ALLOC_NODE_MISMATCH);
3421 goto deactivate_slab;
3422 }
3423 }
3424
3425 /*
3426 * By rights, we should be searching for a slab page that was
3427 * PFMEMALLOC but right now, we are losing the pfmemalloc
3428 * information when the page leaves the per-cpu allocator
3429 */
3430 if (unlikely(!pfmemalloc_match(slab, gfpflags)))
3431 goto deactivate_slab;
3432
3433 /* must check again c->slab in case we got preempted and it changed */
3434 local_lock_irqsave(&s->cpu_slab->lock, flags);
3435 if (unlikely(slab != c->slab)) {
3436 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3437 goto reread_slab;
3438 }
3439 freelist = c->freelist;
3440 if (freelist)
3441 goto load_freelist;
3442
3443 freelist = get_freelist(s, slab);
3444
3445 if (!freelist) {
3446 c->slab = NULL;
3447 c->tid = next_tid(c->tid);
3448 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3449 stat(s, DEACTIVATE_BYPASS);
3450 goto new_slab;
3451 }
3452
3453 stat(s, ALLOC_REFILL);
3454
3455load_freelist:
3456
3457 lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
3458
3459 /*
3460 * freelist is pointing to the list of objects to be used.
3461 * slab is pointing to the slab from which the objects are obtained.
3462 * That slab must be frozen for per cpu allocations to work.
3463 */
3464 VM_BUG_ON(!c->slab->frozen);
3465 c->freelist = get_freepointer(s, freelist);
3466 c->tid = next_tid(c->tid);
3467 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3468 return freelist;
3469
3470deactivate_slab:
3471
3472 local_lock_irqsave(&s->cpu_slab->lock, flags);
3473 if (slab != c->slab) {
3474 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3475 goto reread_slab;
3476 }
3477 freelist = c->freelist;
3478 c->slab = NULL;
3479 c->freelist = NULL;
3480 c->tid = next_tid(c->tid);
3481 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3482 deactivate_slab(s, slab, freelist);
3483
3484new_slab:
3485
3486#ifdef CONFIG_SLUB_CPU_PARTIAL
3487 while (slub_percpu_partial(c)) {
3488 local_lock_irqsave(&s->cpu_slab->lock, flags);
3489 if (unlikely(c->slab)) {
3490 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3491 goto reread_slab;
3492 }
3493 if (unlikely(!slub_percpu_partial(c))) {
3494 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3495 /* we were preempted and partial list got empty */
3496 goto new_objects;
3497 }
3498
3499 slab = slub_percpu_partial(c);
3500 slub_set_percpu_partial(c, slab);
3501 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3502 stat(s, CPU_PARTIAL_ALLOC);
3503
3504 if (unlikely(!node_match(slab, node) ||
3505 !pfmemalloc_match(slab, gfpflags))) {
3506 slab->next = NULL;
3507 __put_partials(s, slab);
3508 continue;
3509 }
3510
3511 freelist = freeze_slab(s, slab);
3512 goto retry_load_slab;
3513 }
3514#endif
3515
3516new_objects:
3517
3518 pc.flags = gfpflags;
3519 pc.orig_size = orig_size;
3520 slab = get_partial(s, node, &pc);
3521 if (slab) {
3522 if (kmem_cache_debug(s)) {
3523 freelist = pc.object;
3524 /*
3525 * For debug caches here we had to go through
3526 * alloc_single_from_partial() so just store the
3527 * tracking info and return the object.
3528 */
3529 if (s->flags & SLAB_STORE_USER)
3530 set_track(s, freelist, TRACK_ALLOC, addr);
3531
3532 return freelist;
3533 }
3534
3535 freelist = freeze_slab(s, slab);
3536 goto retry_load_slab;
3537 }
3538
3539 slub_put_cpu_ptr(s->cpu_slab);
3540 slab = new_slab(s, gfpflags, node);
3541 c = slub_get_cpu_ptr(s->cpu_slab);
3542
3543 if (unlikely(!slab)) {
3544 slab_out_of_memory(s, gfpflags, node);
3545 return NULL;
3546 }
3547
3548 stat(s, ALLOC_SLAB);
3549
3550 if (kmem_cache_debug(s)) {
3551 freelist = alloc_single_from_new_slab(s, slab, orig_size);
3552
3553 if (unlikely(!freelist))
3554 goto new_objects;
3555
3556 if (s->flags & SLAB_STORE_USER)
3557 set_track(s, freelist, TRACK_ALLOC, addr);
3558
3559 return freelist;
3560 }
3561
3562 /*
3563 * No other reference to the slab yet so we can
3564 * muck around with it freely without cmpxchg
3565 */
3566 freelist = slab->freelist;
3567 slab->freelist = NULL;
3568 slab->inuse = slab->objects;
3569 slab->frozen = 1;
3570
3571 inc_slabs_node(s, slab_nid(slab), slab->objects);
3572
3573 if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
3574 /*
3575 * For !pfmemalloc_match() case we don't load freelist so that
3576 * we don't make further mismatched allocations easier.
3577 */
3578 deactivate_slab(s, slab, get_freepointer(s, freelist));
3579 return freelist;
3580 }
3581
3582retry_load_slab:
3583
3584 local_lock_irqsave(&s->cpu_slab->lock, flags);
3585 if (unlikely(c->slab)) {
3586 void *flush_freelist = c->freelist;
3587 struct slab *flush_slab = c->slab;
3588
3589 c->slab = NULL;
3590 c->freelist = NULL;
3591 c->tid = next_tid(c->tid);
3592
3593 local_unlock_irqrestore(&s->cpu_slab->lock, flags);
3594
3595 deactivate_slab(s, flush_slab, flush_freelist);
3596
3597 stat(s, CPUSLAB_FLUSH);
3598
3599 goto retry_load_slab;
3600 }
3601 c->slab = slab;
3602
3603 goto load_freelist;
3604}
3605
3606/*
3607 * A wrapper for ___slab_alloc() for contexts where preemption is not yet
3608 * disabled. Compensates for possible cpu changes by refetching the per cpu area
3609 * pointer.
3610 */
3611static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
3612 unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
3613{
3614 void *p;
3615
3616#ifdef CONFIG_PREEMPT_COUNT
3617 /*
3618 * We may have been preempted and rescheduled on a different
3619 * cpu before disabling preemption. Need to reload cpu area
3620 * pointer.
3621 */
3622 c = slub_get_cpu_ptr(s->cpu_slab);
3623#endif
3624
3625 p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
3626#ifdef CONFIG_PREEMPT_COUNT
3627 slub_put_cpu_ptr(s->cpu_slab);
3628#endif
3629 return p;
3630}
3631
3632static __always_inline void *__slab_alloc_node(struct kmem_cache *s,
3633 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3634{
3635 struct kmem_cache_cpu *c;
3636 struct slab *slab;
3637 unsigned long tid;
3638 void *object;
3639
3640redo:
3641 /*
3642 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
3643 * enabled. We may switch back and forth between cpus while
3644 * reading from one cpu area. That does not matter as long
3645 * as we end up on the original cpu again when doing the cmpxchg.
3646 *
3647 * We must guarantee that tid and kmem_cache_cpu are retrieved on the
3648 * same cpu. We read first the kmem_cache_cpu pointer and use it to read
3649 * the tid. If we are preempted and switched to another cpu between the
3650 * two reads, it's OK as the two are still associated with the same cpu
3651 * and cmpxchg later will validate the cpu.
3652 */
3653 c = raw_cpu_ptr(s->cpu_slab);
3654 tid = READ_ONCE(c->tid);
3655
3656 /*
3657 * Irqless object alloc/free algorithm used here depends on sequence
3658 * of fetching cpu_slab's data. tid should be fetched before anything
3659 * on c to guarantee that object and slab associated with previous tid
3660 * won't be used with current tid. If we fetch tid first, object and
3661 * slab could be one associated with next tid and our alloc/free
3662 * request will be failed. In this case, we will retry. So, no problem.
3663 */
3664 barrier();
3665
3666 /*
3667 * The transaction ids are globally unique per cpu and per operation on
3668 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
3669 * occurs on the right processor and that there was no operation on the
3670 * linked list in between.
3671 */
3672
3673 object = c->freelist;
3674 slab = c->slab;
3675
3676 if (!USE_LOCKLESS_FAST_PATH() ||
3677 unlikely(!object || !slab || !node_match(slab, node))) {
3678 object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
3679 } else {
3680 void *next_object = get_freepointer_safe(s, object);
3681
3682 /*
3683 * The cmpxchg will only match if there was no additional
3684 * operation and if we are on the right processor.
3685 *
3686 * The cmpxchg does the following atomically (without lock
3687 * semantics!)
3688 * 1. Relocate first pointer to the current per cpu area.
3689 * 2. Verify that tid and freelist have not been changed
3690 * 3. If they were not changed replace tid and freelist
3691 *
3692 * Since this is without lock semantics the protection is only
3693 * against code executing on this cpu *not* from access by
3694 * other cpus.
3695 */
3696 if (unlikely(!__update_cpu_freelist_fast(s, object, next_object, tid))) {
3697 note_cmpxchg_failure("slab_alloc", s, tid);
3698 goto redo;
3699 }
3700 prefetch_freepointer(s, next_object);
3701 stat(s, ALLOC_FASTPATH);
3702 }
3703
3704 return object;
3705}
3706#else /* CONFIG_SLUB_TINY */
3707static void *__slab_alloc_node(struct kmem_cache *s,
3708 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3709{
3710 struct partial_context pc;
3711 struct slab *slab;
3712 void *object;
3713
3714 pc.flags = gfpflags;
3715 pc.orig_size = orig_size;
3716 slab = get_partial(s, node, &pc);
3717
3718 if (slab)
3719 return pc.object;
3720
3721 slab = new_slab(s, gfpflags, node);
3722 if (unlikely(!slab)) {
3723 slab_out_of_memory(s, gfpflags, node);
3724 return NULL;
3725 }
3726
3727 object = alloc_single_from_new_slab(s, slab, orig_size);
3728
3729 return object;
3730}
3731#endif /* CONFIG_SLUB_TINY */
3732
3733/*
3734 * If the object has been wiped upon free, make sure it's fully initialized by
3735 * zeroing out freelist pointer.
3736 */
3737static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
3738 void *obj)
3739{
3740 if (unlikely(slab_want_init_on_free(s)) && obj)
3741 memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
3742 0, sizeof(void *));
3743}
3744
3745noinline int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
3746{
3747 if (__should_failslab(s, gfpflags))
3748 return -ENOMEM;
3749 return 0;
3750}
3751ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
3752
3753static __fastpath_inline
3754struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s,
3755 struct list_lru *lru,
3756 struct obj_cgroup **objcgp,
3757 size_t size, gfp_t flags)
3758{
3759 flags &= gfp_allowed_mask;
3760
3761 might_alloc(flags);
3762
3763 if (unlikely(should_failslab(s, flags)))
3764 return NULL;
3765
3766 if (unlikely(!memcg_slab_pre_alloc_hook(s, lru, objcgp, size, flags)))
3767 return NULL;
3768
3769 return s;
3770}
3771
3772static __fastpath_inline
3773void slab_post_alloc_hook(struct kmem_cache *s, struct obj_cgroup *objcg,
3774 gfp_t flags, size_t size, void **p, bool init,
3775 unsigned int orig_size)
3776{
3777 unsigned int zero_size = s->object_size;
3778 bool kasan_init = init;
3779 size_t i;
3780 gfp_t init_flags = flags & gfp_allowed_mask;
3781
3782 /*
3783 * For kmalloc object, the allocated memory size(object_size) is likely
3784 * larger than the requested size(orig_size). If redzone check is
3785 * enabled for the extra space, don't zero it, as it will be redzoned
3786 * soon. The redzone operation for this extra space could be seen as a
3787 * replacement of current poisoning under certain debug option, and
3788 * won't break other sanity checks.
3789 */
3790 if (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) &&
3791 (s->flags & SLAB_KMALLOC))
3792 zero_size = orig_size;
3793
3794 /*
3795 * When slub_debug is enabled, avoid memory initialization integrated
3796 * into KASAN and instead zero out the memory via the memset below with
3797 * the proper size. Otherwise, KASAN might overwrite SLUB redzones and
3798 * cause false-positive reports. This does not lead to a performance
3799 * penalty on production builds, as slub_debug is not intended to be
3800 * enabled there.
3801 */
3802 if (__slub_debug_enabled())
3803 kasan_init = false;
3804
3805 /*
3806 * As memory initialization might be integrated into KASAN,
3807 * kasan_slab_alloc and initialization memset must be
3808 * kept together to avoid discrepancies in behavior.
3809 *
3810 * As p[i] might get tagged, memset and kmemleak hook come after KASAN.
3811 */
3812 for (i = 0; i < size; i++) {
3813 p[i] = kasan_slab_alloc(s, p[i], init_flags, kasan_init);
3814 if (p[i] && init && (!kasan_init ||
3815 !kasan_has_integrated_init()))
3816 memset(p[i], 0, zero_size);
3817 kmemleak_alloc_recursive(p[i], s->object_size, 1,
3818 s->flags, init_flags);
3819 kmsan_slab_alloc(s, p[i], init_flags);
3820 }
3821
3822 memcg_slab_post_alloc_hook(s, objcg, flags, size, p);
3823}
3824
3825/*
3826 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
3827 * have the fastpath folded into their functions. So no function call
3828 * overhead for requests that can be satisfied on the fastpath.
3829 *
3830 * The fastpath works by first checking if the lockless freelist can be used.
3831 * If not then __slab_alloc is called for slow processing.
3832 *
3833 * Otherwise we can simply pick the next object from the lockless free list.
3834 */
3835static __fastpath_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
3836 gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
3837{
3838 void *object;
3839 struct obj_cgroup *objcg = NULL;
3840 bool init = false;
3841
3842 s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
3843 if (unlikely(!s))
3844 return NULL;
3845
3846 object = kfence_alloc(s, orig_size, gfpflags);
3847 if (unlikely(object))
3848 goto out;
3849
3850 object = __slab_alloc_node(s, gfpflags, node, addr, orig_size);
3851
3852 maybe_wipe_obj_freeptr(s, object);
3853 init = slab_want_init_on_alloc(gfpflags, s);
3854
3855out:
3856 /*
3857 * When init equals 'true', like for kzalloc() family, only
3858 * @orig_size bytes might be zeroed instead of s->object_size
3859 */
3860 slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init, orig_size);
3861
3862 return object;
3863}
3864
3865void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
3866{
3867 void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE, _RET_IP_,
3868 s->object_size);
3869
3870 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
3871
3872 return ret;
3873}
3874EXPORT_SYMBOL(kmem_cache_alloc);
3875
3876void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
3877 gfp_t gfpflags)
3878{
3879 void *ret = slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, _RET_IP_,
3880 s->object_size);
3881
3882 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
3883
3884 return ret;
3885}
3886EXPORT_SYMBOL(kmem_cache_alloc_lru);
3887
3888/**
3889 * kmem_cache_alloc_node - Allocate an object on the specified node
3890 * @s: The cache to allocate from.
3891 * @gfpflags: See kmalloc().
3892 * @node: node number of the target node.
3893 *
3894 * Identical to kmem_cache_alloc but it will allocate memory on the given
3895 * node, which can improve the performance for cpu bound structures.
3896 *
3897 * Fallback to other node is possible if __GFP_THISNODE is not set.
3898 *
3899 * Return: pointer to the new object or %NULL in case of error
3900 */
3901void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
3902{
3903 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
3904
3905 trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
3906
3907 return ret;
3908}
3909EXPORT_SYMBOL(kmem_cache_alloc_node);
3910
3911/*
3912 * To avoid unnecessary overhead, we pass through large allocation requests
3913 * directly to the page allocator. We use __GFP_COMP, because we will need to
3914 * know the allocation order to free the pages properly in kfree.
3915 */
3916static void *__kmalloc_large_node(size_t size, gfp_t flags, int node)
3917{
3918 struct folio *folio;
3919 void *ptr = NULL;
3920 unsigned int order = get_order(size);
3921
3922 if (unlikely(flags & GFP_SLAB_BUG_MASK))
3923 flags = kmalloc_fix_flags(flags);
3924
3925 flags |= __GFP_COMP;
3926 folio = (struct folio *)alloc_pages_node(node, flags, order);
3927 if (folio) {
3928 ptr = folio_address(folio);
3929 lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
3930 PAGE_SIZE << order);
3931 }
3932
3933 ptr = kasan_kmalloc_large(ptr, size, flags);
3934 /* As ptr might get tagged, call kmemleak hook after KASAN. */
3935 kmemleak_alloc(ptr, size, 1, flags);
3936 kmsan_kmalloc_large(ptr, size, flags);
3937
3938 return ptr;
3939}
3940
3941void *kmalloc_large(size_t size, gfp_t flags)
3942{
3943 void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);
3944
3945 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
3946 flags, NUMA_NO_NODE);
3947 return ret;
3948}
3949EXPORT_SYMBOL(kmalloc_large);
3950
3951void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3952{
3953 void *ret = __kmalloc_large_node(size, flags, node);
3954
3955 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
3956 flags, node);
3957 return ret;
3958}
3959EXPORT_SYMBOL(kmalloc_large_node);
3960
3961static __always_inline
3962void *__do_kmalloc_node(size_t size, gfp_t flags, int node,
3963 unsigned long caller)
3964{
3965 struct kmem_cache *s;
3966 void *ret;
3967
3968 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
3969 ret = __kmalloc_large_node(size, flags, node);
3970 trace_kmalloc(caller, ret, size,
3971 PAGE_SIZE << get_order(size), flags, node);
3972 return ret;
3973 }
3974
3975 if (unlikely(!size))
3976 return ZERO_SIZE_PTR;
3977
3978 s = kmalloc_slab(size, flags, caller);
3979
3980 ret = slab_alloc_node(s, NULL, flags, node, caller, size);
3981 ret = kasan_kmalloc(s, ret, size, flags);
3982 trace_kmalloc(caller, ret, size, s->size, flags, node);
3983 return ret;
3984}
3985
3986void *__kmalloc_node(size_t size, gfp_t flags, int node)
3987{
3988 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3989}
3990EXPORT_SYMBOL(__kmalloc_node);
3991
3992void *__kmalloc(size_t size, gfp_t flags)
3993{
3994 return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_);
3995}
3996EXPORT_SYMBOL(__kmalloc);
3997
3998void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3999 int node, unsigned long caller)
4000{
4001 return __do_kmalloc_node(size, flags, node, caller);
4002}
4003EXPORT_SYMBOL(__kmalloc_node_track_caller);
4004
4005void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
4006{
4007 void *ret = slab_alloc_node(s, NULL, gfpflags, NUMA_NO_NODE,
4008 _RET_IP_, size);
4009
4010 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
4011
4012 ret = kasan_kmalloc(s, ret, size, gfpflags);
4013 return ret;
4014}
4015EXPORT_SYMBOL(kmalloc_trace);
4016
4017void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
4018 int node, size_t size)
4019{
4020 void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, size);
4021
4022 trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
4023
4024 ret = kasan_kmalloc(s, ret, size, gfpflags);
4025 return ret;
4026}
4027EXPORT_SYMBOL(kmalloc_node_trace);
4028
4029static noinline void free_to_partial_list(
4030 struct kmem_cache *s, struct slab *slab,
4031 void *head, void *tail, int bulk_cnt,
4032 unsigned long addr)
4033{
4034 struct kmem_cache_node *n = get_node(s, slab_nid(slab));
4035 struct slab *slab_free = NULL;
4036 int cnt = bulk_cnt;
4037 unsigned long flags;
4038 depot_stack_handle_t handle = 0;
4039
4040 if (s->flags & SLAB_STORE_USER)
4041 handle = set_track_prepare();
4042
4043 spin_lock_irqsave(&n->list_lock, flags);
4044
4045 if (free_debug_processing(s, slab, head, tail, &cnt, addr, handle)) {
4046 void *prior = slab->freelist;
4047
4048 /* Perform the actual freeing while we still hold the locks */
4049 slab->inuse -= cnt;
4050 set_freepointer(s, tail, prior);
4051 slab->freelist = head;
4052
4053 /*
4054 * If the slab is empty, and node's partial list is full,
4055 * it should be discarded anyway no matter it's on full or
4056 * partial list.
4057 */
4058 if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
4059 slab_free = slab;
4060
4061 if (!prior) {
4062 /* was on full list */
4063 remove_full(s, n, slab);
4064 if (!slab_free) {
4065 add_partial(n, slab, DEACTIVATE_TO_TAIL);
4066 stat(s, FREE_ADD_PARTIAL);
4067 }
4068 } else if (slab_free) {
4069 remove_partial(n, slab);
4070 stat(s, FREE_REMOVE_PARTIAL);
4071 }
4072 }
4073
4074 if (slab_free) {
4075 /*
4076 * Update the counters while still holding n->list_lock to
4077 * prevent spurious validation warnings
4078 */
4079 dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
4080 }
4081
4082 spin_unlock_irqrestore(&n->list_lock, flags);
4083
4084 if (slab_free) {
4085 stat(s, FREE_SLAB);
4086 free_slab(s, slab_free);
4087 }
4088}
4089
4090/*
4091 * Slow path handling. This may still be called frequently since objects
4092 * have a longer lifetime than the cpu slabs in most processing loads.
4093 *
4094 * So we still attempt to reduce cache line usage. Just take the slab
4095 * lock and free the item. If there is no additional partial slab
4096 * handling required then we can return immediately.
4097 */
4098static void __slab_free(struct kmem_cache *s, struct slab *slab,
4099 void *head, void *tail, int cnt,
4100 unsigned long addr)
4101
4102{
4103 void *prior;
4104 int was_frozen;
4105 struct slab new;
4106 unsigned long counters;
4107 struct kmem_cache_node *n = NULL;
4108 unsigned long flags;
4109 bool on_node_partial;
4110
4111 stat(s, FREE_SLOWPATH);
4112
4113 if (IS_ENABLED(CONFIG_SLUB_TINY) || kmem_cache_debug(s)) {
4114 free_to_partial_list(s, slab, head, tail, cnt, addr);
4115 return;
4116 }
4117
4118 do {
4119 if (unlikely(n)) {
4120 spin_unlock_irqrestore(&n->list_lock, flags);
4121 n = NULL;
4122 }
4123 prior = slab->freelist;
4124 counters = slab->counters;
4125 set_freepointer(s, tail, prior);
4126 new.counters = counters;
4127 was_frozen = new.frozen;
4128 new.inuse -= cnt;
4129 if ((!new.inuse || !prior) && !was_frozen) {
4130 /* Needs to be taken off a list */
4131 if (!kmem_cache_has_cpu_partial(s) || prior) {
4132
4133 n = get_node(s, slab_nid(slab));
4134 /*
4135 * Speculatively acquire the list_lock.
4136 * If the cmpxchg does not succeed then we may
4137 * drop the list_lock without any processing.
4138 *
4139 * Otherwise the list_lock will synchronize with
4140 * other processors updating the list of slabs.
4141 */
4142 spin_lock_irqsave(&n->list_lock, flags);
4143
4144 on_node_partial = slab_test_node_partial(slab);
4145 }
4146 }
4147
4148 } while (!slab_update_freelist(s, slab,
4149 prior, counters,
4150 head, new.counters,
4151 "__slab_free"));
4152
4153 if (likely(!n)) {
4154
4155 if (likely(was_frozen)) {
4156 /*
4157 * The list lock was not taken therefore no list
4158 * activity can be necessary.
4159 */
4160 stat(s, FREE_FROZEN);
4161 } else if (kmem_cache_has_cpu_partial(s) && !prior) {
4162 /*
4163 * If we started with a full slab then put it onto the
4164 * per cpu partial list.
4165 */
4166 put_cpu_partial(s, slab, 1);
4167 stat(s, CPU_PARTIAL_FREE);
4168 }
4169
4170 return;
4171 }
4172
4173 /*
4174 * This slab was partially empty but not on the per-node partial list,
4175 * in which case we shouldn't manipulate its list, just return.
4176 */
4177 if (prior && !on_node_partial) {
4178 spin_unlock_irqrestore(&n->list_lock, flags);
4179 return;
4180 }
4181
4182 if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
4183 goto slab_empty;
4184
4185 /*
4186 * Objects left in the slab. If it was not on the partial list before
4187 * then add it.
4188 */
4189 if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
4190 remove_full(s, n, slab);
4191 add_partial(n, slab, DEACTIVATE_TO_TAIL);
4192 stat(s, FREE_ADD_PARTIAL);
4193 }
4194 spin_unlock_irqrestore(&n->list_lock, flags);
4195 return;
4196
4197slab_empty:
4198 if (prior) {
4199 /*
4200 * Slab on the partial list.
4201 */
4202 remove_partial(n, slab);
4203 stat(s, FREE_REMOVE_PARTIAL);
4204 } else {
4205 /* Slab must be on the full list */
4206 remove_full(s, n, slab);
4207 }
4208
4209 spin_unlock_irqrestore(&n->list_lock, flags);
4210 stat(s, FREE_SLAB);
4211 discard_slab(s, slab);
4212}
4213
4214#ifndef CONFIG_SLUB_TINY
4215/*
4216 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
4217 * can perform fastpath freeing without additional function calls.
4218 *
4219 * The fastpath is only possible if we are freeing to the current cpu slab
4220 * of this processor. This typically the case if we have just allocated
4221 * the item before.
4222 *
4223 * If fastpath is not possible then fall back to __slab_free where we deal
4224 * with all sorts of special processing.
4225 *
4226 * Bulk free of a freelist with several objects (all pointing to the
4227 * same slab) possible by specifying head and tail ptr, plus objects
4228 * count (cnt). Bulk free indicated by tail pointer being set.
4229 */
4230static __always_inline void do_slab_free(struct kmem_cache *s,
4231 struct slab *slab, void *head, void *tail,
4232 int cnt, unsigned long addr)
4233{
4234 struct kmem_cache_cpu *c;
4235 unsigned long tid;
4236 void **freelist;
4237
4238redo:
4239 /*
4240 * Determine the currently cpus per cpu slab.
4241 * The cpu may change afterward. However that does not matter since
4242 * data is retrieved via this pointer. If we are on the same cpu
4243 * during the cmpxchg then the free will succeed.
4244 */
4245 c = raw_cpu_ptr(s->cpu_slab);
4246 tid = READ_ONCE(c->tid);
4247
4248 /* Same with comment on barrier() in slab_alloc_node() */
4249 barrier();
4250
4251 if (unlikely(slab != c->slab)) {
4252 __slab_free(s, slab, head, tail, cnt, addr);
4253 return;
4254 }
4255
4256 if (USE_LOCKLESS_FAST_PATH()) {
4257 freelist = READ_ONCE(c->freelist);
4258
4259 set_freepointer(s, tail, freelist);
4260
4261 if (unlikely(!__update_cpu_freelist_fast(s, freelist, head, tid))) {
4262 note_cmpxchg_failure("slab_free", s, tid);
4263 goto redo;
4264 }
4265 } else {
4266 /* Update the free list under the local lock */
4267 local_lock(&s->cpu_slab->lock);
4268 c = this_cpu_ptr(s->cpu_slab);
4269 if (unlikely(slab != c->slab)) {
4270 local_unlock(&s->cpu_slab->lock);
4271 goto redo;
4272 }
4273 tid = c->tid;
4274 freelist = c->freelist;
4275
4276 set_freepointer(s, tail, freelist);
4277 c->freelist = head;
4278 c->tid = next_tid(tid);
4279
4280 local_unlock(&s->cpu_slab->lock);
4281 }
4282 stat_add(s, FREE_FASTPATH, cnt);
4283}
4284#else /* CONFIG_SLUB_TINY */
4285static void do_slab_free(struct kmem_cache *s,
4286 struct slab *slab, void *head, void *tail,
4287 int cnt, unsigned long addr)
4288{
4289 __slab_free(s, slab, head, tail, cnt, addr);
4290}
4291#endif /* CONFIG_SLUB_TINY */
4292
4293static __fastpath_inline
4294void slab_free(struct kmem_cache *s, struct slab *slab, void *object,
4295 unsigned long addr)
4296{
4297 memcg_slab_free_hook(s, slab, &object, 1);
4298
4299 if (likely(slab_free_hook(s, object, slab_want_init_on_free(s))))
4300 do_slab_free(s, slab, object, object, 1, addr);
4301}
4302
4303static __fastpath_inline
4304void slab_free_bulk(struct kmem_cache *s, struct slab *slab, void *head,
4305 void *tail, void **p, int cnt, unsigned long addr)
4306{
4307 memcg_slab_free_hook(s, slab, p, cnt);
4308 /*
4309 * With KASAN enabled slab_free_freelist_hook modifies the freelist
4310 * to remove objects, whose reuse must be delayed.
4311 */
4312 if (likely(slab_free_freelist_hook(s, &head, &tail, &cnt)))
4313 do_slab_free(s, slab, head, tail, cnt, addr);
4314}
4315
4316#ifdef CONFIG_KASAN_GENERIC
4317void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
4318{
4319 do_slab_free(cache, virt_to_slab(x), x, x, 1, addr);
4320}
4321#endif
4322
4323static inline struct kmem_cache *virt_to_cache(const void *obj)
4324{
4325 struct slab *slab;
4326
4327 slab = virt_to_slab(obj);
4328 if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n", __func__))
4329 return NULL;
4330 return slab->slab_cache;
4331}
4332
4333static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
4334{
4335 struct kmem_cache *cachep;
4336
4337 if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) &&
4338 !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS))
4339 return s;
4340
4341 cachep = virt_to_cache(x);
4342 if (WARN(cachep && cachep != s,
4343 "%s: Wrong slab cache. %s but object is from %s\n",
4344 __func__, s->name, cachep->name))
4345 print_tracking(cachep, x);
4346 return cachep;
4347}
4348
4349/**
4350 * kmem_cache_free - Deallocate an object
4351 * @s: The cache the allocation was from.
4352 * @x: The previously allocated object.
4353 *
4354 * Free an object which was previously allocated from this
4355 * cache.
4356 */
4357void kmem_cache_free(struct kmem_cache *s, void *x)
4358{
4359 s = cache_from_obj(s, x);
4360 if (!s)
4361 return;
4362 trace_kmem_cache_free(_RET_IP_, x, s);
4363 slab_free(s, virt_to_slab(x), x, _RET_IP_);
4364}
4365EXPORT_SYMBOL(kmem_cache_free);
4366
4367static void free_large_kmalloc(struct folio *folio, void *object)
4368{
4369 unsigned int order = folio_order(folio);
4370
4371 if (WARN_ON_ONCE(order == 0))
4372 pr_warn_once("object pointer: 0x%p\n", object);
4373
4374 kmemleak_free(object);
4375 kasan_kfree_large(object);
4376 kmsan_kfree_large(object);
4377
4378 lruvec_stat_mod_folio(folio, NR_SLAB_UNRECLAIMABLE_B,
4379 -(PAGE_SIZE << order));
4380 folio_put(folio);
4381}
4382
4383/**
4384 * kfree - free previously allocated memory
4385 * @object: pointer returned by kmalloc() or kmem_cache_alloc()
4386 *
4387 * If @object is NULL, no operation is performed.
4388 */
4389void kfree(const void *object)
4390{
4391 struct folio *folio;
4392 struct slab *slab;
4393 struct kmem_cache *s;
4394 void *x = (void *)object;
4395
4396 trace_kfree(_RET_IP_, object);
4397
4398 if (unlikely(ZERO_OR_NULL_PTR(object)))
4399 return;
4400
4401 folio = virt_to_folio(object);
4402 if (unlikely(!folio_test_slab(folio))) {
4403 free_large_kmalloc(folio, (void *)object);
4404 return;
4405 }
4406
4407 slab = folio_slab(folio);
4408 s = slab->slab_cache;
4409 slab_free(s, slab, x, _RET_IP_);
4410}
4411EXPORT_SYMBOL(kfree);
4412
4413struct detached_freelist {
4414 struct slab *slab;
4415 void *tail;
4416 void *freelist;
4417 int cnt;
4418 struct kmem_cache *s;
4419};
4420
4421/*
4422 * This function progressively scans the array with free objects (with
4423 * a limited look ahead) and extract objects belonging to the same
4424 * slab. It builds a detached freelist directly within the given
4425 * slab/objects. This can happen without any need for
4426 * synchronization, because the objects are owned by running process.
4427 * The freelist is build up as a single linked list in the objects.
4428 * The idea is, that this detached freelist can then be bulk
4429 * transferred to the real freelist(s), but only requiring a single
4430 * synchronization primitive. Look ahead in the array is limited due
4431 * to performance reasons.
4432 */
4433static inline
4434int build_detached_freelist(struct kmem_cache *s, size_t size,
4435 void **p, struct detached_freelist *df)
4436{
4437 int lookahead = 3;
4438 void *object;
4439 struct folio *folio;
4440 size_t same;
4441
4442 object = p[--size];
4443 folio = virt_to_folio(object);
4444 if (!s) {
4445 /* Handle kalloc'ed objects */
4446 if (unlikely(!folio_test_slab(folio))) {
4447 free_large_kmalloc(folio, object);
4448 df->slab = NULL;
4449 return size;
4450 }
4451 /* Derive kmem_cache from object */
4452 df->slab = folio_slab(folio);
4453 df->s = df->slab->slab_cache;
4454 } else {
4455 df->slab = folio_slab(folio);
4456 df->s = cache_from_obj(s, object); /* Support for memcg */
4457 }
4458
4459 /* Start new detached freelist */
4460 df->tail = object;
4461 df->freelist = object;
4462 df->cnt = 1;
4463
4464 if (is_kfence_address(object))
4465 return size;
4466
4467 set_freepointer(df->s, object, NULL);
4468
4469 same = size;
4470 while (size) {
4471 object = p[--size];
4472 /* df->slab is always set at this point */
4473 if (df->slab == virt_to_slab(object)) {
4474 /* Opportunity build freelist */
4475 set_freepointer(df->s, object, df->freelist);
4476 df->freelist = object;
4477 df->cnt++;
4478 same--;
4479 if (size != same)
4480 swap(p[size], p[same]);
4481 continue;
4482 }
4483
4484 /* Limit look ahead search */
4485 if (!--lookahead)
4486 break;
4487 }
4488
4489 return same;
4490}
4491
4492/*
4493 * Internal bulk free of objects that were not initialised by the post alloc
4494 * hooks and thus should not be processed by the free hooks
4495 */
4496static void __kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
4497{
4498 if (!size)
4499 return;
4500
4501 do {
4502 struct detached_freelist df;
4503
4504 size = build_detached_freelist(s, size, p, &df);
4505 if (!df.slab)
4506 continue;
4507
4508 do_slab_free(df.s, df.slab, df.freelist, df.tail, df.cnt,
4509 _RET_IP_);
4510 } while (likely(size));
4511}
4512
4513/* Note that interrupts must be enabled when calling this function. */
4514void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
4515{
4516 if (!size)
4517 return;
4518
4519 do {
4520 struct detached_freelist df;
4521
4522 size = build_detached_freelist(s, size, p, &df);
4523 if (!df.slab)
4524 continue;
4525
4526 slab_free_bulk(df.s, df.slab, df.freelist, df.tail, &p[size],
4527 df.cnt, _RET_IP_);
4528 } while (likely(size));
4529}
4530EXPORT_SYMBOL(kmem_cache_free_bulk);
4531
4532#ifndef CONFIG_SLUB_TINY
4533static inline
4534int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4535 void **p)
4536{
4537 struct kmem_cache_cpu *c;
4538 unsigned long irqflags;
4539 int i;
4540
4541 /*
4542 * Drain objects in the per cpu slab, while disabling local
4543 * IRQs, which protects against PREEMPT and interrupts
4544 * handlers invoking normal fastpath.
4545 */
4546 c = slub_get_cpu_ptr(s->cpu_slab);
4547 local_lock_irqsave(&s->cpu_slab->lock, irqflags);
4548
4549 for (i = 0; i < size; i++) {
4550 void *object = kfence_alloc(s, s->object_size, flags);
4551
4552 if (unlikely(object)) {
4553 p[i] = object;
4554 continue;
4555 }
4556
4557 object = c->freelist;
4558 if (unlikely(!object)) {
4559 /*
4560 * We may have removed an object from c->freelist using
4561 * the fastpath in the previous iteration; in that case,
4562 * c->tid has not been bumped yet.
4563 * Since ___slab_alloc() may reenable interrupts while
4564 * allocating memory, we should bump c->tid now.
4565 */
4566 c->tid = next_tid(c->tid);
4567
4568 local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
4569
4570 /*
4571 * Invoking slow path likely have side-effect
4572 * of re-populating per CPU c->freelist
4573 */
4574 p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
4575 _RET_IP_, c, s->object_size);
4576 if (unlikely(!p[i]))
4577 goto error;
4578
4579 c = this_cpu_ptr(s->cpu_slab);
4580 maybe_wipe_obj_freeptr(s, p[i]);
4581
4582 local_lock_irqsave(&s->cpu_slab->lock, irqflags);
4583
4584 continue; /* goto for-loop */
4585 }
4586 c->freelist = get_freepointer(s, object);
4587 p[i] = object;
4588 maybe_wipe_obj_freeptr(s, p[i]);
4589 stat(s, ALLOC_FASTPATH);
4590 }
4591 c->tid = next_tid(c->tid);
4592 local_unlock_irqrestore(&s->cpu_slab->lock, irqflags);
4593 slub_put_cpu_ptr(s->cpu_slab);
4594
4595 return i;
4596
4597error:
4598 slub_put_cpu_ptr(s->cpu_slab);
4599 __kmem_cache_free_bulk(s, i, p);
4600 return 0;
4601
4602}
4603#else /* CONFIG_SLUB_TINY */
4604static int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags,
4605 size_t size, void **p)
4606{
4607 int i;
4608
4609 for (i = 0; i < size; i++) {
4610 void *object = kfence_alloc(s, s->object_size, flags);
4611
4612 if (unlikely(object)) {
4613 p[i] = object;
4614 continue;
4615 }
4616
4617 p[i] = __slab_alloc_node(s, flags, NUMA_NO_NODE,
4618 _RET_IP_, s->object_size);
4619 if (unlikely(!p[i]))
4620 goto error;
4621
4622 maybe_wipe_obj_freeptr(s, p[i]);
4623 }
4624
4625 return i;
4626
4627error:
4628 __kmem_cache_free_bulk(s, i, p);
4629 return 0;
4630}
4631#endif /* CONFIG_SLUB_TINY */
4632
4633/* Note that interrupts must be enabled when calling this function. */
4634int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
4635 void **p)
4636{
4637 int i;
4638 struct obj_cgroup *objcg = NULL;
4639
4640 if (!size)
4641 return 0;
4642
4643 /* memcg and kmem_cache debug support */
4644 s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
4645 if (unlikely(!s))
4646 return 0;
4647
4648 i = __kmem_cache_alloc_bulk(s, flags, size, p);
4649
4650 /*
4651 * memcg and kmem_cache debug support and memory initialization.
4652 * Done outside of the IRQ disabled fastpath loop.
4653 */
4654 if (likely(i != 0)) {
4655 slab_post_alloc_hook(s, objcg, flags, size, p,
4656 slab_want_init_on_alloc(flags, s), s->object_size);
4657 } else {
4658 memcg_slab_alloc_error_hook(s, size, objcg);
4659 }
4660
4661 return i;
4662}
4663EXPORT_SYMBOL(kmem_cache_alloc_bulk);
4664
4665
4666/*
4667 * Object placement in a slab is made very easy because we always start at
4668 * offset 0. If we tune the size of the object to the alignment then we can
4669 * get the required alignment by putting one properly sized object after
4670 * another.
4671 *
4672 * Notice that the allocation order determines the sizes of the per cpu
4673 * caches. Each processor has always one slab available for allocations.
4674 * Increasing the allocation order reduces the number of times that slabs
4675 * must be moved on and off the partial lists and is therefore a factor in
4676 * locking overhead.
4677 */
4678
4679/*
4680 * Minimum / Maximum order of slab pages. This influences locking overhead
4681 * and slab fragmentation. A higher order reduces the number of partial slabs
4682 * and increases the number of allocations possible without having to
4683 * take the list_lock.
4684 */
4685static unsigned int slub_min_order;
4686static unsigned int slub_max_order =
4687 IS_ENABLED(CONFIG_SLUB_TINY) ? 1 : PAGE_ALLOC_COSTLY_ORDER;
4688static unsigned int slub_min_objects;
4689
4690/*
4691 * Calculate the order of allocation given an slab object size.
4692 *
4693 * The order of allocation has significant impact on performance and other
4694 * system components. Generally order 0 allocations should be preferred since
4695 * order 0 does not cause fragmentation in the page allocator. Larger objects
4696 * be problematic to put into order 0 slabs because there may be too much
4697 * unused space left. We go to a higher order if more than 1/16th of the slab
4698 * would be wasted.
4699 *
4700 * In order to reach satisfactory performance we must ensure that a minimum
4701 * number of objects is in one slab. Otherwise we may generate too much
4702 * activity on the partial lists which requires taking the list_lock. This is
4703 * less a concern for large slabs though which are rarely used.
4704 *
4705 * slub_max_order specifies the order where we begin to stop considering the
4706 * number of objects in a slab as critical. If we reach slub_max_order then
4707 * we try to keep the page order as low as possible. So we accept more waste
4708 * of space in favor of a small page order.
4709 *
4710 * Higher order allocations also allow the placement of more objects in a
4711 * slab and thereby reduce object handling overhead. If the user has
4712 * requested a higher minimum order then we start with that one instead of
4713 * the smallest order which will fit the object.
4714 */
4715static inline unsigned int calc_slab_order(unsigned int size,
4716 unsigned int min_order, unsigned int max_order,
4717 unsigned int fract_leftover)
4718{
4719 unsigned int order;
4720
4721 for (order = min_order; order <= max_order; order++) {
4722
4723 unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
4724 unsigned int rem;
4725
4726 rem = slab_size % size;
4727
4728 if (rem <= slab_size / fract_leftover)
4729 break;
4730 }
4731
4732 return order;
4733}
4734
4735static inline int calculate_order(unsigned int size)
4736{
4737 unsigned int order;
4738 unsigned int min_objects;
4739 unsigned int max_objects;
4740 unsigned int min_order;
4741
4742 min_objects = slub_min_objects;
4743 if (!min_objects) {
4744 /*
4745 * Some architectures will only update present cpus when
4746 * onlining them, so don't trust the number if it's just 1. But
4747 * we also don't want to use nr_cpu_ids always, as on some other
4748 * architectures, there can be many possible cpus, but never
4749 * onlined. Here we compromise between trying to avoid too high
4750 * order on systems that appear larger than they are, and too
4751 * low order on systems that appear smaller than they are.
4752 */
4753 unsigned int nr_cpus = num_present_cpus();
4754 if (nr_cpus <= 1)
4755 nr_cpus = nr_cpu_ids;
4756 min_objects = 4 * (fls(nr_cpus) + 1);
4757 }
4758 /* min_objects can't be 0 because get_order(0) is undefined */
4759 max_objects = max(order_objects(slub_max_order, size), 1U);
4760 min_objects = min(min_objects, max_objects);
4761
4762 min_order = max_t(unsigned int, slub_min_order,
4763 get_order(min_objects * size));
4764 if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
4765 return get_order(size * MAX_OBJS_PER_PAGE) - 1;
4766
4767 /*
4768 * Attempt to find best configuration for a slab. This works by first
4769 * attempting to generate a layout with the best possible configuration
4770 * and backing off gradually.
4771 *
4772 * We start with accepting at most 1/16 waste and try to find the
4773 * smallest order from min_objects-derived/slub_min_order up to
4774 * slub_max_order that will satisfy the constraint. Note that increasing
4775 * the order can only result in same or less fractional waste, not more.
4776 *
4777 * If that fails, we increase the acceptable fraction of waste and try
4778 * again. The last iteration with fraction of 1/2 would effectively
4779 * accept any waste and give us the order determined by min_objects, as
4780 * long as at least single object fits within slub_max_order.
4781 */
4782 for (unsigned int fraction = 16; fraction > 1; fraction /= 2) {
4783 order = calc_slab_order(size, min_order, slub_max_order,
4784 fraction);
4785 if (order <= slub_max_order)
4786 return order;
4787 }
4788
4789 /*
4790 * Doh this slab cannot be placed using slub_max_order.
4791 */
4792 order = get_order(size);
4793 if (order <= MAX_PAGE_ORDER)
4794 return order;
4795 return -ENOSYS;
4796}
4797
4798static void
4799init_kmem_cache_node(struct kmem_cache_node *n)
4800{
4801 n->nr_partial = 0;
4802 spin_lock_init(&n->list_lock);
4803 INIT_LIST_HEAD(&n->partial);
4804#ifdef CONFIG_SLUB_DEBUG
4805 atomic_long_set(&n->nr_slabs, 0);
4806 atomic_long_set(&n->total_objects, 0);
4807 INIT_LIST_HEAD(&n->full);
4808#endif
4809}
4810
4811#ifndef CONFIG_SLUB_TINY
4812static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4813{
4814 BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
4815 NR_KMALLOC_TYPES * KMALLOC_SHIFT_HIGH *
4816 sizeof(struct kmem_cache_cpu));
4817
4818 /*
4819 * Must align to double word boundary for the double cmpxchg
4820 * instructions to work; see __pcpu_double_call_return_bool().
4821 */
4822 s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
4823 2 * sizeof(void *));
4824
4825 if (!s->cpu_slab)
4826 return 0;
4827
4828 init_kmem_cache_cpus(s);
4829
4830 return 1;
4831}
4832#else
4833static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
4834{
4835 return 1;
4836}
4837#endif /* CONFIG_SLUB_TINY */
4838
4839static struct kmem_cache *kmem_cache_node;
4840
4841/*
4842 * No kmalloc_node yet so do it by hand. We know that this is the first
4843 * slab on the node for this slabcache. There are no concurrent accesses
4844 * possible.
4845 *
4846 * Note that this function only works on the kmem_cache_node
4847 * when allocating for the kmem_cache_node. This is used for bootstrapping
4848 * memory on a fresh node that has no slab structures yet.
4849 */
4850static void early_kmem_cache_node_alloc(int node)
4851{
4852 struct slab *slab;
4853 struct kmem_cache_node *n;
4854
4855 BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
4856
4857 slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
4858
4859 BUG_ON(!slab);
4860 inc_slabs_node(kmem_cache_node, slab_nid(slab), slab->objects);
4861 if (slab_nid(slab) != node) {
4862 pr_err("SLUB: Unable to allocate memory from node %d\n", node);
4863 pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
4864 }
4865
4866 n = slab->freelist;
4867 BUG_ON(!n);
4868#ifdef CONFIG_SLUB_DEBUG
4869 init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
4870 init_tracking(kmem_cache_node, n);
4871#endif
4872 n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
4873 slab->freelist = get_freepointer(kmem_cache_node, n);
4874 slab->inuse = 1;
4875 kmem_cache_node->node[node] = n;
4876 init_kmem_cache_node(n);
4877 inc_slabs_node(kmem_cache_node, node, slab->objects);
4878
4879 /*
4880 * No locks need to be taken here as it has just been
4881 * initialized and there is no concurrent access.
4882 */
4883 __add_partial(n, slab, DEACTIVATE_TO_HEAD);
4884}
4885
4886static void free_kmem_cache_nodes(struct kmem_cache *s)
4887{
4888 int node;
4889 struct kmem_cache_node *n;
4890
4891 for_each_kmem_cache_node(s, node, n) {
4892 s->node[node] = NULL;
4893 kmem_cache_free(kmem_cache_node, n);
4894 }
4895}
4896
4897void __kmem_cache_release(struct kmem_cache *s)
4898{
4899 cache_random_seq_destroy(s);
4900#ifndef CONFIG_SLUB_TINY
4901 free_percpu(s->cpu_slab);
4902#endif
4903 free_kmem_cache_nodes(s);
4904}
4905
4906static int init_kmem_cache_nodes(struct kmem_cache *s)
4907{
4908 int node;
4909
4910 for_each_node_mask(node, slab_nodes) {
4911 struct kmem_cache_node *n;
4912
4913 if (slab_state == DOWN) {
4914 early_kmem_cache_node_alloc(node);
4915 continue;
4916 }
4917 n = kmem_cache_alloc_node(kmem_cache_node,
4918 GFP_KERNEL, node);
4919
4920 if (!n) {
4921 free_kmem_cache_nodes(s);
4922 return 0;
4923 }
4924
4925 init_kmem_cache_node(n);
4926 s->node[node] = n;
4927 }
4928 return 1;
4929}
4930
4931static void set_cpu_partial(struct kmem_cache *s)
4932{
4933#ifdef CONFIG_SLUB_CPU_PARTIAL
4934 unsigned int nr_objects;
4935
4936 /*
4937 * cpu_partial determined the maximum number of objects kept in the
4938 * per cpu partial lists of a processor.
4939 *
4940 * Per cpu partial lists mainly contain slabs that just have one
4941 * object freed. If they are used for allocation then they can be
4942 * filled up again with minimal effort. The slab will never hit the
4943 * per node partial lists and therefore no locking will be required.
4944 *
4945 * For backwards compatibility reasons, this is determined as number
4946 * of objects, even though we now limit maximum number of pages, see
4947 * slub_set_cpu_partial()
4948 */
4949 if (!kmem_cache_has_cpu_partial(s))
4950 nr_objects = 0;
4951 else if (s->size >= PAGE_SIZE)
4952 nr_objects = 6;
4953 else if (s->size >= 1024)
4954 nr_objects = 24;
4955 else if (s->size >= 256)
4956 nr_objects = 52;
4957 else
4958 nr_objects = 120;
4959
4960 slub_set_cpu_partial(s, nr_objects);
4961#endif
4962}
4963
4964/*
4965 * calculate_sizes() determines the order and the distribution of data within
4966 * a slab object.
4967 */
4968static int calculate_sizes(struct kmem_cache *s)
4969{
4970 slab_flags_t flags = s->flags;
4971 unsigned int size = s->object_size;
4972 unsigned int order;
4973
4974 /*
4975 * Round up object size to the next word boundary. We can only
4976 * place the free pointer at word boundaries and this determines
4977 * the possible location of the free pointer.
4978 */
4979 size = ALIGN(size, sizeof(void *));
4980
4981#ifdef CONFIG_SLUB_DEBUG
4982 /*
4983 * Determine if we can poison the object itself. If the user of
4984 * the slab may touch the object after free or before allocation
4985 * then we should never poison the object itself.
4986 */
4987 if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
4988 !s->ctor)
4989 s->flags |= __OBJECT_POISON;
4990 else
4991 s->flags &= ~__OBJECT_POISON;
4992
4993
4994 /*
4995 * If we are Redzoning then check if there is some space between the
4996 * end of the object and the free pointer. If not then add an
4997 * additional word to have some bytes to store Redzone information.
4998 */
4999 if ((flags & SLAB_RED_ZONE) && size == s->object_size)
5000 size += sizeof(void *);
5001#endif
5002
5003 /*
5004 * With that we have determined the number of bytes in actual use
5005 * by the object and redzoning.
5006 */
5007 s->inuse = size;
5008
5009 if (slub_debug_orig_size(s) ||
5010 (flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
5011 ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
5012 s->ctor) {
5013 /*
5014 * Relocate free pointer after the object if it is not
5015 * permitted to overwrite the first word of the object on
5016 * kmem_cache_free.
5017 *
5018 * This is the case if we do RCU, have a constructor or
5019 * destructor, are poisoning the objects, or are
5020 * redzoning an object smaller than sizeof(void *).
5021 *
5022 * The assumption that s->offset >= s->inuse means free
5023 * pointer is outside of the object is used in the
5024 * freeptr_outside_object() function. If that is no
5025 * longer true, the function needs to be modified.
5026 */
5027 s->offset = size;
5028 size += sizeof(void *);
5029 } else {
5030 /*
5031 * Store freelist pointer near middle of object to keep
5032 * it away from the edges of the object to avoid small
5033 * sized over/underflows from neighboring allocations.
5034 */
5035 s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
5036 }
5037
5038#ifdef CONFIG_SLUB_DEBUG
5039 if (flags & SLAB_STORE_USER) {
5040 /*
5041 * Need to store information about allocs and frees after
5042 * the object.
5043 */
5044 size += 2 * sizeof(struct track);
5045
5046 /* Save the original kmalloc request size */
5047 if (flags & SLAB_KMALLOC)
5048 size += sizeof(unsigned int);
5049 }
5050#endif
5051
5052 kasan_cache_create(s, &size, &s->flags);
5053#ifdef CONFIG_SLUB_DEBUG
5054 if (flags & SLAB_RED_ZONE) {
5055 /*
5056 * Add some empty padding so that we can catch
5057 * overwrites from earlier objects rather than let
5058 * tracking information or the free pointer be
5059 * corrupted if a user writes before the start
5060 * of the object.
5061 */
5062 size += sizeof(void *);
5063
5064 s->red_left_pad = sizeof(void *);
5065 s->red_left_pad = ALIGN(s->red_left_pad, s->align);
5066 size += s->red_left_pad;
5067 }
5068#endif
5069
5070 /*
5071 * SLUB stores one object immediately after another beginning from
5072 * offset 0. In order to align the objects we have to simply size
5073 * each object to conform to the alignment.
5074 */
5075 size = ALIGN(size, s->align);
5076 s->size = size;
5077 s->reciprocal_size = reciprocal_value(size);
5078 order = calculate_order(size);
5079
5080 if ((int)order < 0)
5081 return 0;
5082
5083 s->allocflags = 0;
5084 if (order)
5085 s->allocflags |= __GFP_COMP;
5086
5087 if (s->flags & SLAB_CACHE_DMA)
5088 s->allocflags |= GFP_DMA;
5089
5090 if (s->flags & SLAB_CACHE_DMA32)
5091 s->allocflags |= GFP_DMA32;
5092
5093 if (s->flags & SLAB_RECLAIM_ACCOUNT)
5094 s->allocflags |= __GFP_RECLAIMABLE;
5095
5096 /*
5097 * Determine the number of objects per slab
5098 */
5099 s->oo = oo_make(order, size);
5100 s->min = oo_make(get_order(size), size);
5101
5102 return !!oo_objects(s->oo);
5103}
5104
5105static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
5106{
5107 s->flags = kmem_cache_flags(s->size, flags, s->name);
5108#ifdef CONFIG_SLAB_FREELIST_HARDENED
5109 s->random = get_random_long();
5110#endif
5111
5112 if (!calculate_sizes(s))
5113 goto error;
5114 if (disable_higher_order_debug) {
5115 /*
5116 * Disable debugging flags that store metadata if the min slab
5117 * order increased.
5118 */
5119 if (get_order(s->size) > get_order(s->object_size)) {
5120 s->flags &= ~DEBUG_METADATA_FLAGS;
5121 s->offset = 0;
5122 if (!calculate_sizes(s))
5123 goto error;
5124 }
5125 }
5126
5127#ifdef system_has_freelist_aba
5128 if (system_has_freelist_aba() && !(s->flags & SLAB_NO_CMPXCHG)) {
5129 /* Enable fast mode */
5130 s->flags |= __CMPXCHG_DOUBLE;
5131 }
5132#endif
5133
5134 /*
5135 * The larger the object size is, the more slabs we want on the partial
5136 * list to avoid pounding the page allocator excessively.
5137 */
5138 s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
5139 s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
5140
5141 set_cpu_partial(s);
5142
5143#ifdef CONFIG_NUMA
5144 s->remote_node_defrag_ratio = 1000;
5145#endif
5146
5147 /* Initialize the pre-computed randomized freelist if slab is up */
5148 if (slab_state >= UP) {
5149 if (init_cache_random_seq(s))
5150 goto error;
5151 }
5152
5153 if (!init_kmem_cache_nodes(s))
5154 goto error;
5155
5156 if (alloc_kmem_cache_cpus(s))
5157 return 0;
5158
5159error:
5160 __kmem_cache_release(s);
5161 return -EINVAL;
5162}
5163
5164static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
5165 const char *text)
5166{
5167#ifdef CONFIG_SLUB_DEBUG
5168 void *addr = slab_address(slab);
5169 void *p;
5170
5171 slab_err(s, slab, text, s->name);
5172
5173 spin_lock(&object_map_lock);
5174 __fill_map(object_map, s, slab);
5175
5176 for_each_object(p, s, addr, slab->objects) {
5177
5178 if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
5179 pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
5180 print_tracking(s, p);
5181 }
5182 }
5183 spin_unlock(&object_map_lock);
5184#endif
5185}
5186
5187/*
5188 * Attempt to free all partial slabs on a node.
5189 * This is called from __kmem_cache_shutdown(). We must take list_lock
5190 * because sysfs file might still access partial list after the shutdowning.
5191 */
5192static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
5193{
5194 LIST_HEAD(discard);
5195 struct slab *slab, *h;
5196
5197 BUG_ON(irqs_disabled());
5198 spin_lock_irq(&n->list_lock);
5199 list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
5200 if (!slab->inuse) {
5201 remove_partial(n, slab);
5202 list_add(&slab->slab_list, &discard);
5203 } else {
5204 list_slab_objects(s, slab,
5205 "Objects remaining in %s on __kmem_cache_shutdown()");
5206 }
5207 }
5208 spin_unlock_irq(&n->list_lock);
5209
5210 list_for_each_entry_safe(slab, h, &discard, slab_list)
5211 discard_slab(s, slab);
5212}
5213
5214bool __kmem_cache_empty(struct kmem_cache *s)
5215{
5216 int node;
5217 struct kmem_cache_node *n;
5218
5219 for_each_kmem_cache_node(s, node, n)
5220 if (n->nr_partial || node_nr_slabs(n))
5221 return false;
5222 return true;
5223}
5224
5225/*
5226 * Release all resources used by a slab cache.
5227 */
5228int __kmem_cache_shutdown(struct kmem_cache *s)
5229{
5230 int node;
5231 struct kmem_cache_node *n;
5232
5233 flush_all_cpus_locked(s);
5234 /* Attempt to free all objects */
5235 for_each_kmem_cache_node(s, node, n) {
5236 free_partial(s, n);
5237 if (n->nr_partial || node_nr_slabs(n))
5238 return 1;
5239 }
5240 return 0;
5241}
5242
5243#ifdef CONFIG_PRINTK
5244void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
5245{
5246 void *base;
5247 int __maybe_unused i;
5248 unsigned int objnr;
5249 void *objp;
5250 void *objp0;
5251 struct kmem_cache *s = slab->slab_cache;
5252 struct track __maybe_unused *trackp;
5253
5254 kpp->kp_ptr = object;
5255 kpp->kp_slab = slab;
5256 kpp->kp_slab_cache = s;
5257 base = slab_address(slab);
5258 objp0 = kasan_reset_tag(object);
5259#ifdef CONFIG_SLUB_DEBUG
5260 objp = restore_red_left(s, objp0);
5261#else
5262 objp = objp0;
5263#endif
5264 objnr = obj_to_index(s, slab, objp);
5265 kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
5266 objp = base + s->size * objnr;
5267 kpp->kp_objp = objp;
5268 if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
5269 || (objp - base) % s->size) ||
5270 !(s->flags & SLAB_STORE_USER))
5271 return;
5272#ifdef CONFIG_SLUB_DEBUG
5273 objp = fixup_red_left(s, objp);
5274 trackp = get_track(s, objp, TRACK_ALLOC);
5275 kpp->kp_ret = (void *)trackp->addr;
5276#ifdef CONFIG_STACKDEPOT
5277 {
5278 depot_stack_handle_t handle;
5279 unsigned long *entries;
5280 unsigned int nr_entries;
5281
5282 handle = READ_ONCE(trackp->handle);
5283 if (handle) {
5284 nr_entries = stack_depot_fetch(handle, &entries);
5285 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
5286 kpp->kp_stack[i] = (void *)entries[i];
5287 }
5288
5289 trackp = get_track(s, objp, TRACK_FREE);
5290 handle = READ_ONCE(trackp->handle);
5291 if (handle) {
5292 nr_entries = stack_depot_fetch(handle, &entries);
5293 for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
5294 kpp->kp_free_stack[i] = (void *)entries[i];
5295 }
5296 }
5297#endif
5298#endif
5299}
5300#endif
5301
5302/********************************************************************
5303 * Kmalloc subsystem
5304 *******************************************************************/
5305
5306static int __init setup_slub_min_order(char *str)
5307{
5308 get_option(&str, (int *)&slub_min_order);
5309
5310 if (slub_min_order > slub_max_order)
5311 slub_max_order = slub_min_order;
5312
5313 return 1;
5314}
5315
5316__setup("slub_min_order=", setup_slub_min_order);
5317
5318static int __init setup_slub_max_order(char *str)
5319{
5320 get_option(&str, (int *)&slub_max_order);
5321 slub_max_order = min_t(unsigned int, slub_max_order, MAX_PAGE_ORDER);
5322
5323 if (slub_min_order > slub_max_order)
5324 slub_min_order = slub_max_order;
5325
5326 return 1;
5327}
5328
5329__setup("slub_max_order=", setup_slub_max_order);
5330
5331static int __init setup_slub_min_objects(char *str)
5332{
5333 get_option(&str, (int *)&slub_min_objects);
5334
5335 return 1;
5336}
5337
5338__setup("slub_min_objects=", setup_slub_min_objects);
5339
5340#ifdef CONFIG_HARDENED_USERCOPY
5341/*
5342 * Rejects incorrectly sized objects and objects that are to be copied
5343 * to/from userspace but do not fall entirely within the containing slab
5344 * cache's usercopy region.
5345 *
5346 * Returns NULL if check passes, otherwise const char * to name of cache
5347 * to indicate an error.
5348 */
5349void __check_heap_object(const void *ptr, unsigned long n,
5350 const struct slab *slab, bool to_user)
5351{
5352 struct kmem_cache *s;
5353 unsigned int offset;
5354 bool is_kfence = is_kfence_address(ptr);
5355
5356 ptr = kasan_reset_tag(ptr);
5357
5358 /* Find object and usable object size. */
5359 s = slab->slab_cache;
5360
5361 /* Reject impossible pointers. */
5362 if (ptr < slab_address(slab))
5363 usercopy_abort("SLUB object not in SLUB page?!", NULL,
5364 to_user, 0, n);
5365
5366 /* Find offset within object. */
5367 if (is_kfence)
5368 offset = ptr - kfence_object_start(ptr);
5369 else
5370 offset = (ptr - slab_address(slab)) % s->size;
5371
5372 /* Adjust for redzone and reject if within the redzone. */
5373 if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
5374 if (offset < s->red_left_pad)
5375 usercopy_abort("SLUB object in left red zone",
5376 s->name, to_user, offset, n);
5377 offset -= s->red_left_pad;
5378 }
5379
5380 /* Allow address range falling entirely within usercopy region. */
5381 if (offset >= s->useroffset &&
5382 offset - s->useroffset <= s->usersize &&
5383 n <= s->useroffset - offset + s->usersize)
5384 return;
5385
5386 usercopy_abort("SLUB object", s->name, to_user, offset, n);
5387}
5388#endif /* CONFIG_HARDENED_USERCOPY */
5389
5390#define SHRINK_PROMOTE_MAX 32
5391
5392/*
5393 * kmem_cache_shrink discards empty slabs and promotes the slabs filled
5394 * up most to the head of the partial lists. New allocations will then
5395 * fill those up and thus they can be removed from the partial lists.
5396 *
5397 * The slabs with the least items are placed last. This results in them
5398 * being allocated from last increasing the chance that the last objects
5399 * are freed in them.
5400 */
5401static int __kmem_cache_do_shrink(struct kmem_cache *s)
5402{
5403 int node;
5404 int i;
5405 struct kmem_cache_node *n;
5406 struct slab *slab;
5407 struct slab *t;
5408 struct list_head discard;
5409 struct list_head promote[SHRINK_PROMOTE_MAX];
5410 unsigned long flags;
5411 int ret = 0;
5412
5413 for_each_kmem_cache_node(s, node, n) {
5414 INIT_LIST_HEAD(&discard);
5415 for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
5416 INIT_LIST_HEAD(promote + i);
5417
5418 spin_lock_irqsave(&n->list_lock, flags);
5419
5420 /*
5421 * Build lists of slabs to discard or promote.
5422 *
5423 * Note that concurrent frees may occur while we hold the
5424 * list_lock. slab->inuse here is the upper limit.
5425 */
5426 list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
5427 int free = slab->objects - slab->inuse;
5428
5429 /* Do not reread slab->inuse */
5430 barrier();
5431
5432 /* We do not keep full slabs on the list */
5433 BUG_ON(free <= 0);
5434
5435 if (free == slab->objects) {
5436 list_move(&slab->slab_list, &discard);
5437 slab_clear_node_partial(slab);
5438 n->nr_partial--;
5439 dec_slabs_node(s, node, slab->objects);
5440 } else if (free <= SHRINK_PROMOTE_MAX)
5441 list_move(&slab->slab_list, promote + free - 1);
5442 }
5443
5444 /*
5445 * Promote the slabs filled up most to the head of the
5446 * partial list.
5447 */
5448 for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
5449 list_splice(promote + i, &n->partial);
5450
5451 spin_unlock_irqrestore(&n->list_lock, flags);
5452
5453 /* Release empty slabs */
5454 list_for_each_entry_safe(slab, t, &discard, slab_list)
5455 free_slab(s, slab);
5456
5457 if (node_nr_slabs(n))
5458 ret = 1;
5459 }
5460
5461 return ret;
5462}
5463
5464int __kmem_cache_shrink(struct kmem_cache *s)
5465{
5466 flush_all(s);
5467 return __kmem_cache_do_shrink(s);
5468}
5469
5470static int slab_mem_going_offline_callback(void *arg)
5471{
5472 struct kmem_cache *s;
5473
5474 mutex_lock(&slab_mutex);
5475 list_for_each_entry(s, &slab_caches, list) {
5476 flush_all_cpus_locked(s);
5477 __kmem_cache_do_shrink(s);
5478 }
5479 mutex_unlock(&slab_mutex);
5480
5481 return 0;
5482}
5483
5484static void slab_mem_offline_callback(void *arg)
5485{
5486 struct memory_notify *marg = arg;
5487 int offline_node;
5488
5489 offline_node = marg->status_change_nid_normal;
5490
5491 /*
5492 * If the node still has available memory. we need kmem_cache_node
5493 * for it yet.
5494 */
5495 if (offline_node < 0)
5496 return;
5497
5498 mutex_lock(&slab_mutex);
5499 node_clear(offline_node, slab_nodes);
5500 /*
5501 * We no longer free kmem_cache_node structures here, as it would be
5502 * racy with all get_node() users, and infeasible to protect them with
5503 * slab_mutex.
5504 */
5505 mutex_unlock(&slab_mutex);
5506}
5507
5508static int slab_mem_going_online_callback(void *arg)
5509{
5510 struct kmem_cache_node *n;
5511 struct kmem_cache *s;
5512 struct memory_notify *marg = arg;
5513 int nid = marg->status_change_nid_normal;
5514 int ret = 0;
5515
5516 /*
5517 * If the node's memory is already available, then kmem_cache_node is
5518 * already created. Nothing to do.
5519 */
5520 if (nid < 0)
5521 return 0;
5522
5523 /*
5524 * We are bringing a node online. No memory is available yet. We must
5525 * allocate a kmem_cache_node structure in order to bring the node
5526 * online.
5527 */
5528 mutex_lock(&slab_mutex);
5529 list_for_each_entry(s, &slab_caches, list) {
5530 /*
5531 * The structure may already exist if the node was previously
5532 * onlined and offlined.
5533 */
5534 if (get_node(s, nid))
5535 continue;
5536 /*
5537 * XXX: kmem_cache_alloc_node will fallback to other nodes
5538 * since memory is not yet available from the node that
5539 * is brought up.
5540 */
5541 n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
5542 if (!n) {
5543 ret = -ENOMEM;
5544 goto out;
5545 }
5546 init_kmem_cache_node(n);
5547 s->node[nid] = n;
5548 }
5549 /*
5550 * Any cache created after this point will also have kmem_cache_node
5551 * initialized for the new node.
5552 */
5553 node_set(nid, slab_nodes);
5554out:
5555 mutex_unlock(&slab_mutex);
5556 return ret;
5557}
5558
5559static int slab_memory_callback(struct notifier_block *self,
5560 unsigned long action, void *arg)
5561{
5562 int ret = 0;
5563
5564 switch (action) {
5565 case MEM_GOING_ONLINE:
5566 ret = slab_mem_going_online_callback(arg);
5567 break;
5568 case MEM_GOING_OFFLINE:
5569 ret = slab_mem_going_offline_callback(arg);
5570 break;
5571 case MEM_OFFLINE:
5572 case MEM_CANCEL_ONLINE:
5573 slab_mem_offline_callback(arg);
5574 break;
5575 case MEM_ONLINE:
5576 case MEM_CANCEL_OFFLINE:
5577 break;
5578 }
5579 if (ret)
5580 ret = notifier_from_errno(ret);
5581 else
5582 ret = NOTIFY_OK;
5583 return ret;
5584}
5585
5586/********************************************************************
5587 * Basic setup of slabs
5588 *******************************************************************/
5589
5590/*
5591 * Used for early kmem_cache structures that were allocated using
5592 * the page allocator. Allocate them properly then fix up the pointers
5593 * that may be pointing to the wrong kmem_cache structure.
5594 */
5595
5596static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
5597{
5598 int node;
5599 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
5600 struct kmem_cache_node *n;
5601
5602 memcpy(s, static_cache, kmem_cache->object_size);
5603
5604 /*
5605 * This runs very early, and only the boot processor is supposed to be
5606 * up. Even if it weren't true, IRQs are not up so we couldn't fire
5607 * IPIs around.
5608 */
5609 __flush_cpu_slab(s, smp_processor_id());
5610 for_each_kmem_cache_node(s, node, n) {
5611 struct slab *p;
5612
5613 list_for_each_entry(p, &n->partial, slab_list)
5614 p->slab_cache = s;
5615
5616#ifdef CONFIG_SLUB_DEBUG
5617 list_for_each_entry(p, &n->full, slab_list)
5618 p->slab_cache = s;
5619#endif
5620 }
5621 list_add(&s->list, &slab_caches);
5622 return s;
5623}
5624
5625void __init kmem_cache_init(void)
5626{
5627 static __initdata struct kmem_cache boot_kmem_cache,
5628 boot_kmem_cache_node;
5629 int node;
5630
5631 if (debug_guardpage_minorder())
5632 slub_max_order = 0;
5633
5634 /* Print slub debugging pointers without hashing */
5635 if (__slub_debug_enabled())
5636 no_hash_pointers_enable(NULL);
5637
5638 kmem_cache_node = &boot_kmem_cache_node;
5639 kmem_cache = &boot_kmem_cache;
5640
5641 /*
5642 * Initialize the nodemask for which we will allocate per node
5643 * structures. Here we don't need taking slab_mutex yet.
5644 */
5645 for_each_node_state(node, N_NORMAL_MEMORY)
5646 node_set(node, slab_nodes);
5647
5648 create_boot_cache(kmem_cache_node, "kmem_cache_node",
5649 sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
5650
5651 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
5652
5653 /* Able to allocate the per node structures */
5654 slab_state = PARTIAL;
5655
5656 create_boot_cache(kmem_cache, "kmem_cache",
5657 offsetof(struct kmem_cache, node) +
5658 nr_node_ids * sizeof(struct kmem_cache_node *),
5659 SLAB_HWCACHE_ALIGN, 0, 0);
5660
5661 kmem_cache = bootstrap(&boot_kmem_cache);
5662 kmem_cache_node = bootstrap(&boot_kmem_cache_node);
5663
5664 /* Now we can use the kmem_cache to allocate kmalloc slabs */
5665 setup_kmalloc_cache_index_table();
5666 create_kmalloc_caches(0);
5667
5668 /* Setup random freelists for each cache */
5669 init_freelist_randomization();
5670
5671 cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
5672 slub_cpu_dead);
5673
5674 pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
5675 cache_line_size(),
5676 slub_min_order, slub_max_order, slub_min_objects,
5677 nr_cpu_ids, nr_node_ids);
5678}
5679
5680void __init kmem_cache_init_late(void)
5681{
5682#ifndef CONFIG_SLUB_TINY
5683 flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
5684 WARN_ON(!flushwq);
5685#endif
5686}
5687
5688struct kmem_cache *
5689__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
5690 slab_flags_t flags, void (*ctor)(void *))
5691{
5692 struct kmem_cache *s;
5693
5694 s = find_mergeable(size, align, flags, name, ctor);
5695 if (s) {
5696 if (sysfs_slab_alias(s, name))
5697 return NULL;
5698
5699 s->refcount++;
5700
5701 /*
5702 * Adjust the object sizes so that we clear
5703 * the complete object on kzalloc.
5704 */
5705 s->object_size = max(s->object_size, size);
5706 s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
5707 }
5708
5709 return s;
5710}
5711
5712int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
5713{
5714 int err;
5715
5716 err = kmem_cache_open(s, flags);
5717 if (err)
5718 return err;
5719
5720 /* Mutex is not taken during early boot */
5721 if (slab_state <= UP)
5722 return 0;
5723
5724 err = sysfs_slab_add(s);
5725 if (err) {
5726 __kmem_cache_release(s);
5727 return err;
5728 }
5729
5730 if (s->flags & SLAB_STORE_USER)
5731 debugfs_slab_add(s);
5732
5733 return 0;
5734}
5735
5736#ifdef SLAB_SUPPORTS_SYSFS
5737static int count_inuse(struct slab *slab)
5738{
5739 return slab->inuse;
5740}
5741
5742static int count_total(struct slab *slab)
5743{
5744 return slab->objects;
5745}
5746#endif
5747
5748#ifdef CONFIG_SLUB_DEBUG
5749static void validate_slab(struct kmem_cache *s, struct slab *slab,
5750 unsigned long *obj_map)
5751{
5752 void *p;
5753 void *addr = slab_address(slab);
5754
5755 if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
5756 return;
5757
5758 /* Now we know that a valid freelist exists */
5759 __fill_map(obj_map, s, slab);
5760 for_each_object(p, s, addr, slab->objects) {
5761 u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
5762 SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
5763
5764 if (!check_object(s, slab, p, val))
5765 break;
5766 }
5767}
5768
5769static int validate_slab_node(struct kmem_cache *s,
5770 struct kmem_cache_node *n, unsigned long *obj_map)
5771{
5772 unsigned long count = 0;
5773 struct slab *slab;
5774 unsigned long flags;
5775
5776 spin_lock_irqsave(&n->list_lock, flags);
5777
5778 list_for_each_entry(slab, &n->partial, slab_list) {
5779 validate_slab(s, slab, obj_map);
5780 count++;
5781 }
5782 if (count != n->nr_partial) {
5783 pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
5784 s->name, count, n->nr_partial);
5785 slab_add_kunit_errors();
5786 }
5787
5788 if (!(s->flags & SLAB_STORE_USER))
5789 goto out;
5790
5791 list_for_each_entry(slab, &n->full, slab_list) {
5792 validate_slab(s, slab, obj_map);
5793 count++;
5794 }
5795 if (count != node_nr_slabs(n)) {
5796 pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
5797 s->name, count, node_nr_slabs(n));
5798 slab_add_kunit_errors();
5799 }
5800
5801out:
5802 spin_unlock_irqrestore(&n->list_lock, flags);
5803 return count;
5804}
5805
5806long validate_slab_cache(struct kmem_cache *s)
5807{
5808 int node;
5809 unsigned long count = 0;
5810 struct kmem_cache_node *n;
5811 unsigned long *obj_map;
5812
5813 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
5814 if (!obj_map)
5815 return -ENOMEM;
5816
5817 flush_all(s);
5818 for_each_kmem_cache_node(s, node, n)
5819 count += validate_slab_node(s, n, obj_map);
5820
5821 bitmap_free(obj_map);
5822
5823 return count;
5824}
5825EXPORT_SYMBOL(validate_slab_cache);
5826
5827#ifdef CONFIG_DEBUG_FS
5828/*
5829 * Generate lists of code addresses where slabcache objects are allocated
5830 * and freed.
5831 */
5832
5833struct location {
5834 depot_stack_handle_t handle;
5835 unsigned long count;
5836 unsigned long addr;
5837 unsigned long waste;
5838 long long sum_time;
5839 long min_time;
5840 long max_time;
5841 long min_pid;
5842 long max_pid;
5843 DECLARE_BITMAP(cpus, NR_CPUS);
5844 nodemask_t nodes;
5845};
5846
5847struct loc_track {
5848 unsigned long max;
5849 unsigned long count;
5850 struct location *loc;
5851 loff_t idx;
5852};
5853
5854static struct dentry *slab_debugfs_root;
5855
5856static void free_loc_track(struct loc_track *t)
5857{
5858 if (t->max)
5859 free_pages((unsigned long)t->loc,
5860 get_order(sizeof(struct location) * t->max));
5861}
5862
5863static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
5864{
5865 struct location *l;
5866 int order;
5867
5868 order = get_order(sizeof(struct location) * max);
5869
5870 l = (void *)__get_free_pages(flags, order);
5871 if (!l)
5872 return 0;
5873
5874 if (t->count) {
5875 memcpy(l, t->loc, sizeof(struct location) * t->count);
5876 free_loc_track(t);
5877 }
5878 t->max = max;
5879 t->loc = l;
5880 return 1;
5881}
5882
5883static int add_location(struct loc_track *t, struct kmem_cache *s,
5884 const struct track *track,
5885 unsigned int orig_size)
5886{
5887 long start, end, pos;
5888 struct location *l;
5889 unsigned long caddr, chandle, cwaste;
5890 unsigned long age = jiffies - track->when;
5891 depot_stack_handle_t handle = 0;
5892 unsigned int waste = s->object_size - orig_size;
5893
5894#ifdef CONFIG_STACKDEPOT
5895 handle = READ_ONCE(track->handle);
5896#endif
5897 start = -1;
5898 end = t->count;
5899
5900 for ( ; ; ) {
5901 pos = start + (end - start + 1) / 2;
5902
5903 /*
5904 * There is nothing at "end". If we end up there
5905 * we need to add something to before end.
5906 */
5907 if (pos == end)
5908 break;
5909
5910 l = &t->loc[pos];
5911 caddr = l->addr;
5912 chandle = l->handle;
5913 cwaste = l->waste;
5914 if ((track->addr == caddr) && (handle == chandle) &&
5915 (waste == cwaste)) {
5916
5917 l->count++;
5918 if (track->when) {
5919 l->sum_time += age;
5920 if (age < l->min_time)
5921 l->min_time = age;
5922 if (age > l->max_time)
5923 l->max_time = age;
5924
5925 if (track->pid < l->min_pid)
5926 l->min_pid = track->pid;
5927 if (track->pid > l->max_pid)
5928 l->max_pid = track->pid;
5929
5930 cpumask_set_cpu(track->cpu,
5931 to_cpumask(l->cpus));
5932 }
5933 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5934 return 1;
5935 }
5936
5937 if (track->addr < caddr)
5938 end = pos;
5939 else if (track->addr == caddr && handle < chandle)
5940 end = pos;
5941 else if (track->addr == caddr && handle == chandle &&
5942 waste < cwaste)
5943 end = pos;
5944 else
5945 start = pos;
5946 }
5947
5948 /*
5949 * Not found. Insert new tracking element.
5950 */
5951 if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
5952 return 0;
5953
5954 l = t->loc + pos;
5955 if (pos < t->count)
5956 memmove(l + 1, l,
5957 (t->count - pos) * sizeof(struct location));
5958 t->count++;
5959 l->count = 1;
5960 l->addr = track->addr;
5961 l->sum_time = age;
5962 l->min_time = age;
5963 l->max_time = age;
5964 l->min_pid = track->pid;
5965 l->max_pid = track->pid;
5966 l->handle = handle;
5967 l->waste = waste;
5968 cpumask_clear(to_cpumask(l->cpus));
5969 cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
5970 nodes_clear(l->nodes);
5971 node_set(page_to_nid(virt_to_page(track)), l->nodes);
5972 return 1;
5973}
5974
5975static void process_slab(struct loc_track *t, struct kmem_cache *s,
5976 struct slab *slab, enum track_item alloc,
5977 unsigned long *obj_map)
5978{
5979 void *addr = slab_address(slab);
5980 bool is_alloc = (alloc == TRACK_ALLOC);
5981 void *p;
5982
5983 __fill_map(obj_map, s, slab);
5984
5985 for_each_object(p, s, addr, slab->objects)
5986 if (!test_bit(__obj_to_index(s, addr, p), obj_map))
5987 add_location(t, s, get_track(s, p, alloc),
5988 is_alloc ? get_orig_size(s, p) :
5989 s->object_size);
5990}
5991#endif /* CONFIG_DEBUG_FS */
5992#endif /* CONFIG_SLUB_DEBUG */
5993
5994#ifdef SLAB_SUPPORTS_SYSFS
5995enum slab_stat_type {
5996 SL_ALL, /* All slabs */
5997 SL_PARTIAL, /* Only partially allocated slabs */
5998 SL_CPU, /* Only slabs used for cpu caches */
5999 SL_OBJECTS, /* Determine allocated objects not slabs */
6000 SL_TOTAL /* Determine object capacity not slabs */
6001};
6002
6003#define SO_ALL (1 << SL_ALL)
6004#define SO_PARTIAL (1 << SL_PARTIAL)
6005#define SO_CPU (1 << SL_CPU)
6006#define SO_OBJECTS (1 << SL_OBJECTS)
6007#define SO_TOTAL (1 << SL_TOTAL)
6008
6009static ssize_t show_slab_objects(struct kmem_cache *s,
6010 char *buf, unsigned long flags)
6011{
6012 unsigned long total = 0;
6013 int node;
6014 int x;
6015 unsigned long *nodes;
6016 int len = 0;
6017
6018 nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
6019 if (!nodes)
6020 return -ENOMEM;
6021
6022 if (flags & SO_CPU) {
6023 int cpu;
6024
6025 for_each_possible_cpu(cpu) {
6026 struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
6027 cpu);
6028 int node;
6029 struct slab *slab;
6030
6031 slab = READ_ONCE(c->slab);
6032 if (!slab)
6033 continue;
6034
6035 node = slab_nid(slab);
6036 if (flags & SO_TOTAL)
6037 x = slab->objects;
6038 else if (flags & SO_OBJECTS)
6039 x = slab->inuse;
6040 else
6041 x = 1;
6042
6043 total += x;
6044 nodes[node] += x;
6045
6046#ifdef CONFIG_SLUB_CPU_PARTIAL
6047 slab = slub_percpu_partial_read_once(c);
6048 if (slab) {
6049 node = slab_nid(slab);
6050 if (flags & SO_TOTAL)
6051 WARN_ON_ONCE(1);
6052 else if (flags & SO_OBJECTS)
6053 WARN_ON_ONCE(1);
6054 else
6055 x = slab->slabs;
6056 total += x;
6057 nodes[node] += x;
6058 }
6059#endif
6060 }
6061 }
6062
6063 /*
6064 * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
6065 * already held which will conflict with an existing lock order:
6066 *
6067 * mem_hotplug_lock->slab_mutex->kernfs_mutex
6068 *
6069 * We don't really need mem_hotplug_lock (to hold off
6070 * slab_mem_going_offline_callback) here because slab's memory hot
6071 * unplug code doesn't destroy the kmem_cache->node[] data.
6072 */
6073
6074#ifdef CONFIG_SLUB_DEBUG
6075 if (flags & SO_ALL) {
6076 struct kmem_cache_node *n;
6077
6078 for_each_kmem_cache_node(s, node, n) {
6079
6080 if (flags & SO_TOTAL)
6081 x = node_nr_objs(n);
6082 else if (flags & SO_OBJECTS)
6083 x = node_nr_objs(n) - count_partial(n, count_free);
6084 else
6085 x = node_nr_slabs(n);
6086 total += x;
6087 nodes[node] += x;
6088 }
6089
6090 } else
6091#endif
6092 if (flags & SO_PARTIAL) {
6093 struct kmem_cache_node *n;
6094
6095 for_each_kmem_cache_node(s, node, n) {
6096 if (flags & SO_TOTAL)
6097 x = count_partial(n, count_total);
6098 else if (flags & SO_OBJECTS)
6099 x = count_partial(n, count_inuse);
6100 else
6101 x = n->nr_partial;
6102 total += x;
6103 nodes[node] += x;
6104 }
6105 }
6106
6107 len += sysfs_emit_at(buf, len, "%lu", total);
6108#ifdef CONFIG_NUMA
6109 for (node = 0; node < nr_node_ids; node++) {
6110 if (nodes[node])
6111 len += sysfs_emit_at(buf, len, " N%d=%lu",
6112 node, nodes[node]);
6113 }
6114#endif
6115 len += sysfs_emit_at(buf, len, "\n");
6116 kfree(nodes);
6117
6118 return len;
6119}
6120
6121#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
6122#define to_slab(n) container_of(n, struct kmem_cache, kobj)
6123
6124struct slab_attribute {
6125 struct attribute attr;
6126 ssize_t (*show)(struct kmem_cache *s, char *buf);
6127 ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
6128};
6129
6130#define SLAB_ATTR_RO(_name) \
6131 static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
6132
6133#define SLAB_ATTR(_name) \
6134 static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
6135
6136static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
6137{
6138 return sysfs_emit(buf, "%u\n", s->size);
6139}
6140SLAB_ATTR_RO(slab_size);
6141
6142static ssize_t align_show(struct kmem_cache *s, char *buf)
6143{
6144 return sysfs_emit(buf, "%u\n", s->align);
6145}
6146SLAB_ATTR_RO(align);
6147
6148static ssize_t object_size_show(struct kmem_cache *s, char *buf)
6149{
6150 return sysfs_emit(buf, "%u\n", s->object_size);
6151}
6152SLAB_ATTR_RO(object_size);
6153
6154static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
6155{
6156 return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
6157}
6158SLAB_ATTR_RO(objs_per_slab);
6159
6160static ssize_t order_show(struct kmem_cache *s, char *buf)
6161{
6162 return sysfs_emit(buf, "%u\n", oo_order(s->oo));
6163}
6164SLAB_ATTR_RO(order);
6165
6166static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
6167{
6168 return sysfs_emit(buf, "%lu\n", s->min_partial);
6169}
6170
6171static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
6172 size_t length)
6173{
6174 unsigned long min;
6175 int err;
6176
6177 err = kstrtoul(buf, 10, &min);
6178 if (err)
6179 return err;
6180
6181 s->min_partial = min;
6182 return length;
6183}
6184SLAB_ATTR(min_partial);
6185
6186static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
6187{
6188 unsigned int nr_partial = 0;
6189#ifdef CONFIG_SLUB_CPU_PARTIAL
6190 nr_partial = s->cpu_partial;
6191#endif
6192
6193 return sysfs_emit(buf, "%u\n", nr_partial);
6194}
6195
6196static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
6197 size_t length)
6198{
6199 unsigned int objects;
6200 int err;
6201
6202 err = kstrtouint(buf, 10, &objects);
6203 if (err)
6204 return err;
6205 if (objects && !kmem_cache_has_cpu_partial(s))
6206 return -EINVAL;
6207
6208 slub_set_cpu_partial(s, objects);
6209 flush_all(s);
6210 return length;
6211}
6212SLAB_ATTR(cpu_partial);
6213
6214static ssize_t ctor_show(struct kmem_cache *s, char *buf)
6215{
6216 if (!s->ctor)
6217 return 0;
6218 return sysfs_emit(buf, "%pS\n", s->ctor);
6219}
6220SLAB_ATTR_RO(ctor);
6221
6222static ssize_t aliases_show(struct kmem_cache *s, char *buf)
6223{
6224 return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
6225}
6226SLAB_ATTR_RO(aliases);
6227
6228static ssize_t partial_show(struct kmem_cache *s, char *buf)
6229{
6230 return show_slab_objects(s, buf, SO_PARTIAL);
6231}
6232SLAB_ATTR_RO(partial);
6233
6234static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
6235{
6236 return show_slab_objects(s, buf, SO_CPU);
6237}
6238SLAB_ATTR_RO(cpu_slabs);
6239
6240static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
6241{
6242 return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
6243}
6244SLAB_ATTR_RO(objects_partial);
6245
6246static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
6247{
6248 int objects = 0;
6249 int slabs = 0;
6250 int cpu __maybe_unused;
6251 int len = 0;
6252
6253#ifdef CONFIG_SLUB_CPU_PARTIAL
6254 for_each_online_cpu(cpu) {
6255 struct slab *slab;
6256
6257 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
6258
6259 if (slab)
6260 slabs += slab->slabs;
6261 }
6262#endif
6263
6264 /* Approximate half-full slabs, see slub_set_cpu_partial() */
6265 objects = (slabs * oo_objects(s->oo)) / 2;
6266 len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
6267
6268#ifdef CONFIG_SLUB_CPU_PARTIAL
6269 for_each_online_cpu(cpu) {
6270 struct slab *slab;
6271
6272 slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
6273 if (slab) {
6274 slabs = READ_ONCE(slab->slabs);
6275 objects = (slabs * oo_objects(s->oo)) / 2;
6276 len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
6277 cpu, objects, slabs);
6278 }
6279 }
6280#endif
6281 len += sysfs_emit_at(buf, len, "\n");
6282
6283 return len;
6284}
6285SLAB_ATTR_RO(slabs_cpu_partial);
6286
6287static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
6288{
6289 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
6290}
6291SLAB_ATTR_RO(reclaim_account);
6292
6293static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
6294{
6295 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
6296}
6297SLAB_ATTR_RO(hwcache_align);
6298
6299#ifdef CONFIG_ZONE_DMA
6300static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
6301{
6302 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
6303}
6304SLAB_ATTR_RO(cache_dma);
6305#endif
6306
6307#ifdef CONFIG_HARDENED_USERCOPY
6308static ssize_t usersize_show(struct kmem_cache *s, char *buf)
6309{
6310 return sysfs_emit(buf, "%u\n", s->usersize);
6311}
6312SLAB_ATTR_RO(usersize);
6313#endif
6314
6315static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
6316{
6317 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
6318}
6319SLAB_ATTR_RO(destroy_by_rcu);
6320
6321#ifdef CONFIG_SLUB_DEBUG
6322static ssize_t slabs_show(struct kmem_cache *s, char *buf)
6323{
6324 return show_slab_objects(s, buf, SO_ALL);
6325}
6326SLAB_ATTR_RO(slabs);
6327
6328static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
6329{
6330 return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
6331}
6332SLAB_ATTR_RO(total_objects);
6333
6334static ssize_t objects_show(struct kmem_cache *s, char *buf)
6335{
6336 return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
6337}
6338SLAB_ATTR_RO(objects);
6339
6340static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
6341{
6342 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
6343}
6344SLAB_ATTR_RO(sanity_checks);
6345
6346static ssize_t trace_show(struct kmem_cache *s, char *buf)
6347{
6348 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
6349}
6350SLAB_ATTR_RO(trace);
6351
6352static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
6353{
6354 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
6355}
6356
6357SLAB_ATTR_RO(red_zone);
6358
6359static ssize_t poison_show(struct kmem_cache *s, char *buf)
6360{
6361 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
6362}
6363
6364SLAB_ATTR_RO(poison);
6365
6366static ssize_t store_user_show(struct kmem_cache *s, char *buf)
6367{
6368 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
6369}
6370
6371SLAB_ATTR_RO(store_user);
6372
6373static ssize_t validate_show(struct kmem_cache *s, char *buf)
6374{
6375 return 0;
6376}
6377
6378static ssize_t validate_store(struct kmem_cache *s,
6379 const char *buf, size_t length)
6380{
6381 int ret = -EINVAL;
6382
6383 if (buf[0] == '1' && kmem_cache_debug(s)) {
6384 ret = validate_slab_cache(s);
6385 if (ret >= 0)
6386 ret = length;
6387 }
6388 return ret;
6389}
6390SLAB_ATTR(validate);
6391
6392#endif /* CONFIG_SLUB_DEBUG */
6393
6394#ifdef CONFIG_FAILSLAB
6395static ssize_t failslab_show(struct kmem_cache *s, char *buf)
6396{
6397 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
6398}
6399
6400static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
6401 size_t length)
6402{
6403 if (s->refcount > 1)
6404 return -EINVAL;
6405
6406 if (buf[0] == '1')
6407 WRITE_ONCE(s->flags, s->flags | SLAB_FAILSLAB);
6408 else
6409 WRITE_ONCE(s->flags, s->flags & ~SLAB_FAILSLAB);
6410
6411 return length;
6412}
6413SLAB_ATTR(failslab);
6414#endif
6415
6416static ssize_t shrink_show(struct kmem_cache *s, char *buf)
6417{
6418 return 0;
6419}
6420
6421static ssize_t shrink_store(struct kmem_cache *s,
6422 const char *buf, size_t length)
6423{
6424 if (buf[0] == '1')
6425 kmem_cache_shrink(s);
6426 else
6427 return -EINVAL;
6428 return length;
6429}
6430SLAB_ATTR(shrink);
6431
6432#ifdef CONFIG_NUMA
6433static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
6434{
6435 return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
6436}
6437
6438static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
6439 const char *buf, size_t length)
6440{
6441 unsigned int ratio;
6442 int err;
6443
6444 err = kstrtouint(buf, 10, &ratio);
6445 if (err)
6446 return err;
6447 if (ratio > 100)
6448 return -ERANGE;
6449
6450 s->remote_node_defrag_ratio = ratio * 10;
6451
6452 return length;
6453}
6454SLAB_ATTR(remote_node_defrag_ratio);
6455#endif
6456
6457#ifdef CONFIG_SLUB_STATS
6458static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
6459{
6460 unsigned long sum = 0;
6461 int cpu;
6462 int len = 0;
6463 int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
6464
6465 if (!data)
6466 return -ENOMEM;
6467
6468 for_each_online_cpu(cpu) {
6469 unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
6470
6471 data[cpu] = x;
6472 sum += x;
6473 }
6474
6475 len += sysfs_emit_at(buf, len, "%lu", sum);
6476
6477#ifdef CONFIG_SMP
6478 for_each_online_cpu(cpu) {
6479 if (data[cpu])
6480 len += sysfs_emit_at(buf, len, " C%d=%u",
6481 cpu, data[cpu]);
6482 }
6483#endif
6484 kfree(data);
6485 len += sysfs_emit_at(buf, len, "\n");
6486
6487 return len;
6488}
6489
6490static void clear_stat(struct kmem_cache *s, enum stat_item si)
6491{
6492 int cpu;
6493
6494 for_each_online_cpu(cpu)
6495 per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
6496}
6497
6498#define STAT_ATTR(si, text) \
6499static ssize_t text##_show(struct kmem_cache *s, char *buf) \
6500{ \
6501 return show_stat(s, buf, si); \
6502} \
6503static ssize_t text##_store(struct kmem_cache *s, \
6504 const char *buf, size_t length) \
6505{ \
6506 if (buf[0] != '0') \
6507 return -EINVAL; \
6508 clear_stat(s, si); \
6509 return length; \
6510} \
6511SLAB_ATTR(text); \
6512
6513STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
6514STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
6515STAT_ATTR(FREE_FASTPATH, free_fastpath);
6516STAT_ATTR(FREE_SLOWPATH, free_slowpath);
6517STAT_ATTR(FREE_FROZEN, free_frozen);
6518STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
6519STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
6520STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
6521STAT_ATTR(ALLOC_SLAB, alloc_slab);
6522STAT_ATTR(ALLOC_REFILL, alloc_refill);
6523STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
6524STAT_ATTR(FREE_SLAB, free_slab);
6525STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
6526STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
6527STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
6528STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
6529STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
6530STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
6531STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
6532STAT_ATTR(ORDER_FALLBACK, order_fallback);
6533STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
6534STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
6535STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
6536STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
6537STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
6538STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
6539#endif /* CONFIG_SLUB_STATS */
6540
6541#ifdef CONFIG_KFENCE
6542static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
6543{
6544 return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
6545}
6546
6547static ssize_t skip_kfence_store(struct kmem_cache *s,
6548 const char *buf, size_t length)
6549{
6550 int ret = length;
6551
6552 if (buf[0] == '0')
6553 s->flags &= ~SLAB_SKIP_KFENCE;
6554 else if (buf[0] == '1')
6555 s->flags |= SLAB_SKIP_KFENCE;
6556 else
6557 ret = -EINVAL;
6558
6559 return ret;
6560}
6561SLAB_ATTR(skip_kfence);
6562#endif
6563
6564static struct attribute *slab_attrs[] = {
6565 &slab_size_attr.attr,
6566 &object_size_attr.attr,
6567 &objs_per_slab_attr.attr,
6568 &order_attr.attr,
6569 &min_partial_attr.attr,
6570 &cpu_partial_attr.attr,
6571 &objects_partial_attr.attr,
6572 &partial_attr.attr,
6573 &cpu_slabs_attr.attr,
6574 &ctor_attr.attr,
6575 &aliases_attr.attr,
6576 &align_attr.attr,
6577 &hwcache_align_attr.attr,
6578 &reclaim_account_attr.attr,
6579 &destroy_by_rcu_attr.attr,
6580 &shrink_attr.attr,
6581 &slabs_cpu_partial_attr.attr,
6582#ifdef CONFIG_SLUB_DEBUG
6583 &total_objects_attr.attr,
6584 &objects_attr.attr,
6585 &slabs_attr.attr,
6586 &sanity_checks_attr.attr,
6587 &trace_attr.attr,
6588 &red_zone_attr.attr,
6589 &poison_attr.attr,
6590 &store_user_attr.attr,
6591 &validate_attr.attr,
6592#endif
6593#ifdef CONFIG_ZONE_DMA
6594 &cache_dma_attr.attr,
6595#endif
6596#ifdef CONFIG_NUMA
6597 &remote_node_defrag_ratio_attr.attr,
6598#endif
6599#ifdef CONFIG_SLUB_STATS
6600 &alloc_fastpath_attr.attr,
6601 &alloc_slowpath_attr.attr,
6602 &free_fastpath_attr.attr,
6603 &free_slowpath_attr.attr,
6604 &free_frozen_attr.attr,
6605 &free_add_partial_attr.attr,
6606 &free_remove_partial_attr.attr,
6607 &alloc_from_partial_attr.attr,
6608 &alloc_slab_attr.attr,
6609 &alloc_refill_attr.attr,
6610 &alloc_node_mismatch_attr.attr,
6611 &free_slab_attr.attr,
6612 &cpuslab_flush_attr.attr,
6613 &deactivate_full_attr.attr,
6614 &deactivate_empty_attr.attr,
6615 &deactivate_to_head_attr.attr,
6616 &deactivate_to_tail_attr.attr,
6617 &deactivate_remote_frees_attr.attr,
6618 &deactivate_bypass_attr.attr,
6619 &order_fallback_attr.attr,
6620 &cmpxchg_double_fail_attr.attr,
6621 &cmpxchg_double_cpu_fail_attr.attr,
6622 &cpu_partial_alloc_attr.attr,
6623 &cpu_partial_free_attr.attr,
6624 &cpu_partial_node_attr.attr,
6625 &cpu_partial_drain_attr.attr,
6626#endif
6627#ifdef CONFIG_FAILSLAB
6628 &failslab_attr.attr,
6629#endif
6630#ifdef CONFIG_HARDENED_USERCOPY
6631 &usersize_attr.attr,
6632#endif
6633#ifdef CONFIG_KFENCE
6634 &skip_kfence_attr.attr,
6635#endif
6636
6637 NULL
6638};
6639
6640static const struct attribute_group slab_attr_group = {
6641 .attrs = slab_attrs,
6642};
6643
6644static ssize_t slab_attr_show(struct kobject *kobj,
6645 struct attribute *attr,
6646 char *buf)
6647{
6648 struct slab_attribute *attribute;
6649 struct kmem_cache *s;
6650
6651 attribute = to_slab_attr(attr);
6652 s = to_slab(kobj);
6653
6654 if (!attribute->show)
6655 return -EIO;
6656
6657 return attribute->show(s, buf);
6658}
6659
6660static ssize_t slab_attr_store(struct kobject *kobj,
6661 struct attribute *attr,
6662 const char *buf, size_t len)
6663{
6664 struct slab_attribute *attribute;
6665 struct kmem_cache *s;
6666
6667 attribute = to_slab_attr(attr);
6668 s = to_slab(kobj);
6669
6670 if (!attribute->store)
6671 return -EIO;
6672
6673 return attribute->store(s, buf, len);
6674}
6675
6676static void kmem_cache_release(struct kobject *k)
6677{
6678 slab_kmem_cache_release(to_slab(k));
6679}
6680
6681static const struct sysfs_ops slab_sysfs_ops = {
6682 .show = slab_attr_show,
6683 .store = slab_attr_store,
6684};
6685
6686static const struct kobj_type slab_ktype = {
6687 .sysfs_ops = &slab_sysfs_ops,
6688 .release = kmem_cache_release,
6689};
6690
6691static struct kset *slab_kset;
6692
6693static inline struct kset *cache_kset(struct kmem_cache *s)
6694{
6695 return slab_kset;
6696}
6697
6698#define ID_STR_LENGTH 32
6699
6700/* Create a unique string id for a slab cache:
6701 *
6702 * Format :[flags-]size
6703 */
6704static char *create_unique_id(struct kmem_cache *s)
6705{
6706 char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
6707 char *p = name;
6708
6709 if (!name)
6710 return ERR_PTR(-ENOMEM);
6711
6712 *p++ = ':';
6713 /*
6714 * First flags affecting slabcache operations. We will only
6715 * get here for aliasable slabs so we do not need to support
6716 * too many flags. The flags here must cover all flags that
6717 * are matched during merging to guarantee that the id is
6718 * unique.
6719 */
6720 if (s->flags & SLAB_CACHE_DMA)
6721 *p++ = 'd';
6722 if (s->flags & SLAB_CACHE_DMA32)
6723 *p++ = 'D';
6724 if (s->flags & SLAB_RECLAIM_ACCOUNT)
6725 *p++ = 'a';
6726 if (s->flags & SLAB_CONSISTENCY_CHECKS)
6727 *p++ = 'F';
6728 if (s->flags & SLAB_ACCOUNT)
6729 *p++ = 'A';
6730 if (p != name + 1)
6731 *p++ = '-';
6732 p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
6733
6734 if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
6735 kfree(name);
6736 return ERR_PTR(-EINVAL);
6737 }
6738 kmsan_unpoison_memory(name, p - name);
6739 return name;
6740}
6741
6742static int sysfs_slab_add(struct kmem_cache *s)
6743{
6744 int err;
6745 const char *name;
6746 struct kset *kset = cache_kset(s);
6747 int unmergeable = slab_unmergeable(s);
6748
6749 if (!unmergeable && disable_higher_order_debug &&
6750 (slub_debug & DEBUG_METADATA_FLAGS))
6751 unmergeable = 1;
6752
6753 if (unmergeable) {
6754 /*
6755 * Slabcache can never be merged so we can use the name proper.
6756 * This is typically the case for debug situations. In that
6757 * case we can catch duplicate names easily.
6758 */
6759 sysfs_remove_link(&slab_kset->kobj, s->name);
6760 name = s->name;
6761 } else {
6762 /*
6763 * Create a unique name for the slab as a target
6764 * for the symlinks.
6765 */
6766 name = create_unique_id(s);
6767 if (IS_ERR(name))
6768 return PTR_ERR(name);
6769 }
6770
6771 s->kobj.kset = kset;
6772 err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
6773 if (err)
6774 goto out;
6775
6776 err = sysfs_create_group(&s->kobj, &slab_attr_group);
6777 if (err)
6778 goto out_del_kobj;
6779
6780 if (!unmergeable) {
6781 /* Setup first alias */
6782 sysfs_slab_alias(s, s->name);
6783 }
6784out:
6785 if (!unmergeable)
6786 kfree(name);
6787 return err;
6788out_del_kobj:
6789 kobject_del(&s->kobj);
6790 goto out;
6791}
6792
6793void sysfs_slab_unlink(struct kmem_cache *s)
6794{
6795 if (slab_state >= FULL)
6796 kobject_del(&s->kobj);
6797}
6798
6799void sysfs_slab_release(struct kmem_cache *s)
6800{
6801 if (slab_state >= FULL)
6802 kobject_put(&s->kobj);
6803}
6804
6805/*
6806 * Need to buffer aliases during bootup until sysfs becomes
6807 * available lest we lose that information.
6808 */
6809struct saved_alias {
6810 struct kmem_cache *s;
6811 const char *name;
6812 struct saved_alias *next;
6813};
6814
6815static struct saved_alias *alias_list;
6816
6817static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
6818{
6819 struct saved_alias *al;
6820
6821 if (slab_state == FULL) {
6822 /*
6823 * If we have a leftover link then remove it.
6824 */
6825 sysfs_remove_link(&slab_kset->kobj, name);
6826 return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
6827 }
6828
6829 al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
6830 if (!al)
6831 return -ENOMEM;
6832
6833 al->s = s;
6834 al->name = name;
6835 al->next = alias_list;
6836 alias_list = al;
6837 kmsan_unpoison_memory(al, sizeof(*al));
6838 return 0;
6839}
6840
6841static int __init slab_sysfs_init(void)
6842{
6843 struct kmem_cache *s;
6844 int err;
6845
6846 mutex_lock(&slab_mutex);
6847
6848 slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
6849 if (!slab_kset) {
6850 mutex_unlock(&slab_mutex);
6851 pr_err("Cannot register slab subsystem.\n");
6852 return -ENOMEM;
6853 }
6854
6855 slab_state = FULL;
6856
6857 list_for_each_entry(s, &slab_caches, list) {
6858 err = sysfs_slab_add(s);
6859 if (err)
6860 pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
6861 s->name);
6862 }
6863
6864 while (alias_list) {
6865 struct saved_alias *al = alias_list;
6866
6867 alias_list = alias_list->next;
6868 err = sysfs_slab_alias(al->s, al->name);
6869 if (err)
6870 pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
6871 al->name);
6872 kfree(al);
6873 }
6874
6875 mutex_unlock(&slab_mutex);
6876 return 0;
6877}
6878late_initcall(slab_sysfs_init);
6879#endif /* SLAB_SUPPORTS_SYSFS */
6880
6881#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
6882static int slab_debugfs_show(struct seq_file *seq, void *v)
6883{
6884 struct loc_track *t = seq->private;
6885 struct location *l;
6886 unsigned long idx;
6887
6888 idx = (unsigned long) t->idx;
6889 if (idx < t->count) {
6890 l = &t->loc[idx];
6891
6892 seq_printf(seq, "%7ld ", l->count);
6893
6894 if (l->addr)
6895 seq_printf(seq, "%pS", (void *)l->addr);
6896 else
6897 seq_puts(seq, "<not-available>");
6898
6899 if (l->waste)
6900 seq_printf(seq, " waste=%lu/%lu",
6901 l->count * l->waste, l->waste);
6902
6903 if (l->sum_time != l->min_time) {
6904 seq_printf(seq, " age=%ld/%llu/%ld",
6905 l->min_time, div_u64(l->sum_time, l->count),
6906 l->max_time);
6907 } else
6908 seq_printf(seq, " age=%ld", l->min_time);
6909
6910 if (l->min_pid != l->max_pid)
6911 seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
6912 else
6913 seq_printf(seq, " pid=%ld",
6914 l->min_pid);
6915
6916 if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
6917 seq_printf(seq, " cpus=%*pbl",
6918 cpumask_pr_args(to_cpumask(l->cpus)));
6919
6920 if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
6921 seq_printf(seq, " nodes=%*pbl",
6922 nodemask_pr_args(&l->nodes));
6923
6924#ifdef CONFIG_STACKDEPOT
6925 {
6926 depot_stack_handle_t handle;
6927 unsigned long *entries;
6928 unsigned int nr_entries, j;
6929
6930 handle = READ_ONCE(l->handle);
6931 if (handle) {
6932 nr_entries = stack_depot_fetch(handle, &entries);
6933 seq_puts(seq, "\n");
6934 for (j = 0; j < nr_entries; j++)
6935 seq_printf(seq, " %pS\n", (void *)entries[j]);
6936 }
6937 }
6938#endif
6939 seq_puts(seq, "\n");
6940 }
6941
6942 if (!idx && !t->count)
6943 seq_puts(seq, "No data\n");
6944
6945 return 0;
6946}
6947
6948static void slab_debugfs_stop(struct seq_file *seq, void *v)
6949{
6950}
6951
6952static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
6953{
6954 struct loc_track *t = seq->private;
6955
6956 t->idx = ++(*ppos);
6957 if (*ppos <= t->count)
6958 return ppos;
6959
6960 return NULL;
6961}
6962
6963static int cmp_loc_by_count(const void *a, const void *b, const void *data)
6964{
6965 struct location *loc1 = (struct location *)a;
6966 struct location *loc2 = (struct location *)b;
6967
6968 if (loc1->count > loc2->count)
6969 return -1;
6970 else
6971 return 1;
6972}
6973
6974static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
6975{
6976 struct loc_track *t = seq->private;
6977
6978 t->idx = *ppos;
6979 return ppos;
6980}
6981
6982static const struct seq_operations slab_debugfs_sops = {
6983 .start = slab_debugfs_start,
6984 .next = slab_debugfs_next,
6985 .stop = slab_debugfs_stop,
6986 .show = slab_debugfs_show,
6987};
6988
6989static int slab_debug_trace_open(struct inode *inode, struct file *filep)
6990{
6991
6992 struct kmem_cache_node *n;
6993 enum track_item alloc;
6994 int node;
6995 struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
6996 sizeof(struct loc_track));
6997 struct kmem_cache *s = file_inode(filep)->i_private;
6998 unsigned long *obj_map;
6999
7000 if (!t)
7001 return -ENOMEM;
7002
7003 obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
7004 if (!obj_map) {
7005 seq_release_private(inode, filep);
7006 return -ENOMEM;
7007 }
7008
7009 if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
7010 alloc = TRACK_ALLOC;
7011 else
7012 alloc = TRACK_FREE;
7013
7014 if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
7015 bitmap_free(obj_map);
7016 seq_release_private(inode, filep);
7017 return -ENOMEM;
7018 }
7019
7020 for_each_kmem_cache_node(s, node, n) {
7021 unsigned long flags;
7022 struct slab *slab;
7023
7024 if (!node_nr_slabs(n))
7025 continue;
7026
7027 spin_lock_irqsave(&n->list_lock, flags);
7028 list_for_each_entry(slab, &n->partial, slab_list)
7029 process_slab(t, s, slab, alloc, obj_map);
7030 list_for_each_entry(slab, &n->full, slab_list)
7031 process_slab(t, s, slab, alloc, obj_map);
7032 spin_unlock_irqrestore(&n->list_lock, flags);
7033 }
7034
7035 /* Sort locations by count */
7036 sort_r(t->loc, t->count, sizeof(struct location),
7037 cmp_loc_by_count, NULL, NULL);
7038
7039 bitmap_free(obj_map);
7040 return 0;
7041}
7042
7043static int slab_debug_trace_release(struct inode *inode, struct file *file)
7044{
7045 struct seq_file *seq = file->private_data;
7046 struct loc_track *t = seq->private;
7047
7048 free_loc_track(t);
7049 return seq_release_private(inode, file);
7050}
7051
7052static const struct file_operations slab_debugfs_fops = {
7053 .open = slab_debug_trace_open,
7054 .read = seq_read,
7055 .llseek = seq_lseek,
7056 .release = slab_debug_trace_release,
7057};
7058
7059static void debugfs_slab_add(struct kmem_cache *s)
7060{
7061 struct dentry *slab_cache_dir;
7062
7063 if (unlikely(!slab_debugfs_root))
7064 return;
7065
7066 slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
7067
7068 debugfs_create_file("alloc_traces", 0400,
7069 slab_cache_dir, s, &slab_debugfs_fops);
7070
7071 debugfs_create_file("free_traces", 0400,
7072 slab_cache_dir, s, &slab_debugfs_fops);
7073}
7074
7075void debugfs_slab_release(struct kmem_cache *s)
7076{
7077 debugfs_lookup_and_remove(s->name, slab_debugfs_root);
7078}
7079
7080static int __init slab_debugfs_init(void)
7081{
7082 struct kmem_cache *s;
7083
7084 slab_debugfs_root = debugfs_create_dir("slab", NULL);
7085
7086 list_for_each_entry(s, &slab_caches, list)
7087 if (s->flags & SLAB_STORE_USER)
7088 debugfs_slab_add(s);
7089
7090 return 0;
7091
7092}
7093__initcall(slab_debugfs_init);
7094#endif
7095/*
7096 * The /proc/slabinfo ABI
7097 */
7098#ifdef CONFIG_SLUB_DEBUG
7099void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
7100{
7101 unsigned long nr_slabs = 0;
7102 unsigned long nr_objs = 0;
7103 unsigned long nr_free = 0;
7104 int node;
7105 struct kmem_cache_node *n;
7106
7107 for_each_kmem_cache_node(s, node, n) {
7108 nr_slabs += node_nr_slabs(n);
7109 nr_objs += node_nr_objs(n);
7110 nr_free += count_partial(n, count_free);
7111 }
7112
7113 sinfo->active_objs = nr_objs - nr_free;
7114 sinfo->num_objs = nr_objs;
7115 sinfo->active_slabs = nr_slabs;
7116 sinfo->num_slabs = nr_slabs;
7117 sinfo->objects_per_slab = oo_objects(s->oo);
7118 sinfo->cache_order = oo_order(s->oo);
7119}
7120
7121void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
7122{
7123}
7124
7125ssize_t slabinfo_write(struct file *file, const char __user *buffer,
7126 size_t count, loff_t *ppos)
7127{
7128 return -EIO;
7129}
7130#endif /* CONFIG_SLUB_DEBUG */