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