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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Slab allocator functions that are independent of the allocator strategy
4 *
5 * (C) 2012 Christoph Lameter <cl@linux.com>
6 */
7#include <linux/slab.h>
8
9#include <linux/mm.h>
10#include <linux/poison.h>
11#include <linux/interrupt.h>
12#include <linux/memory.h>
13#include <linux/cache.h>
14#include <linux/compiler.h>
15#include <linux/kfence.h>
16#include <linux/module.h>
17#include <linux/cpu.h>
18#include <linux/uaccess.h>
19#include <linux/seq_file.h>
20#include <linux/dma-mapping.h>
21#include <linux/swiotlb.h>
22#include <linux/proc_fs.h>
23#include <linux/debugfs.h>
24#include <linux/kmemleak.h>
25#include <linux/kasan.h>
26#include <asm/cacheflush.h>
27#include <asm/tlbflush.h>
28#include <asm/page.h>
29#include <linux/memcontrol.h>
30#include <linux/stackdepot.h>
31
32#include "internal.h"
33#include "slab.h"
34
35#define CREATE_TRACE_POINTS
36#include <trace/events/kmem.h>
37
38enum slab_state slab_state;
39LIST_HEAD(slab_caches);
40DEFINE_MUTEX(slab_mutex);
41struct kmem_cache *kmem_cache;
42
43static LIST_HEAD(slab_caches_to_rcu_destroy);
44static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
45static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
46 slab_caches_to_rcu_destroy_workfn);
47
48/*
49 * Set of flags that will prevent slab merging
50 */
51#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
52 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
53 SLAB_FAILSLAB | SLAB_NO_MERGE)
54
55#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
56 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
57
58/*
59 * Merge control. If this is set then no merging of slab caches will occur.
60 */
61static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
62
63static int __init setup_slab_nomerge(char *str)
64{
65 slab_nomerge = true;
66 return 1;
67}
68
69static int __init setup_slab_merge(char *str)
70{
71 slab_nomerge = false;
72 return 1;
73}
74
75__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
76__setup_param("slub_merge", slub_merge, setup_slab_merge, 0);
77
78__setup("slab_nomerge", setup_slab_nomerge);
79__setup("slab_merge", setup_slab_merge);
80
81/*
82 * Determine the size of a slab object
83 */
84unsigned int kmem_cache_size(struct kmem_cache *s)
85{
86 return s->object_size;
87}
88EXPORT_SYMBOL(kmem_cache_size);
89
90#ifdef CONFIG_DEBUG_VM
91static int kmem_cache_sanity_check(const char *name, unsigned int size)
92{
93 if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) {
94 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
95 return -EINVAL;
96 }
97
98 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
99 return 0;
100}
101#else
102static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
103{
104 return 0;
105}
106#endif
107
108/*
109 * Figure out what the alignment of the objects will be given a set of
110 * flags, a user specified alignment and the size of the objects.
111 */
112static unsigned int calculate_alignment(slab_flags_t flags,
113 unsigned int align, unsigned int size)
114{
115 /*
116 * If the user wants hardware cache aligned objects then follow that
117 * suggestion if the object is sufficiently large.
118 *
119 * The hardware cache alignment cannot override the specified
120 * alignment though. If that is greater then use it.
121 */
122 if (flags & SLAB_HWCACHE_ALIGN) {
123 unsigned int ralign;
124
125 ralign = cache_line_size();
126 while (size <= ralign / 2)
127 ralign /= 2;
128 align = max(align, ralign);
129 }
130
131 align = max(align, arch_slab_minalign());
132
133 return ALIGN(align, sizeof(void *));
134}
135
136/*
137 * Find a mergeable slab cache
138 */
139int slab_unmergeable(struct kmem_cache *s)
140{
141 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
142 return 1;
143
144 if (s->ctor)
145 return 1;
146
147#ifdef CONFIG_HARDENED_USERCOPY
148 if (s->usersize)
149 return 1;
150#endif
151
152 /*
153 * We may have set a slab to be unmergeable during bootstrap.
154 */
155 if (s->refcount < 0)
156 return 1;
157
158 return 0;
159}
160
161struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
162 slab_flags_t flags, const char *name, void (*ctor)(void *))
163{
164 struct kmem_cache *s;
165
166 if (slab_nomerge)
167 return NULL;
168
169 if (ctor)
170 return NULL;
171
172 size = ALIGN(size, sizeof(void *));
173 align = calculate_alignment(flags, align, size);
174 size = ALIGN(size, align);
175 flags = kmem_cache_flags(flags, name);
176
177 if (flags & SLAB_NEVER_MERGE)
178 return NULL;
179
180 list_for_each_entry_reverse(s, &slab_caches, list) {
181 if (slab_unmergeable(s))
182 continue;
183
184 if (size > s->size)
185 continue;
186
187 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
188 continue;
189 /*
190 * Check if alignment is compatible.
191 * Courtesy of Adrian Drzewiecki
192 */
193 if ((s->size & ~(align - 1)) != s->size)
194 continue;
195
196 if (s->size - size >= sizeof(void *))
197 continue;
198
199 return s;
200 }
201 return NULL;
202}
203
204static struct kmem_cache *create_cache(const char *name,
205 unsigned int object_size, unsigned int align,
206 slab_flags_t flags, unsigned int useroffset,
207 unsigned int usersize, void (*ctor)(void *),
208 struct kmem_cache *root_cache)
209{
210 struct kmem_cache *s;
211 int err;
212
213 if (WARN_ON(useroffset + usersize > object_size))
214 useroffset = usersize = 0;
215
216 err = -ENOMEM;
217 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
218 if (!s)
219 goto out;
220
221 s->name = name;
222 s->size = s->object_size = object_size;
223 s->align = align;
224 s->ctor = ctor;
225#ifdef CONFIG_HARDENED_USERCOPY
226 s->useroffset = useroffset;
227 s->usersize = usersize;
228#endif
229
230 err = __kmem_cache_create(s, flags);
231 if (err)
232 goto out_free_cache;
233
234 s->refcount = 1;
235 list_add(&s->list, &slab_caches);
236 return s;
237
238out_free_cache:
239 kmem_cache_free(kmem_cache, s);
240out:
241 return ERR_PTR(err);
242}
243
244/**
245 * kmem_cache_create_usercopy - Create a cache with a region suitable
246 * for copying to userspace
247 * @name: A string which is used in /proc/slabinfo to identify this cache.
248 * @size: The size of objects to be created in this cache.
249 * @align: The required alignment for the objects.
250 * @flags: SLAB flags
251 * @useroffset: Usercopy region offset
252 * @usersize: Usercopy region size
253 * @ctor: A constructor for the objects.
254 *
255 * Cannot be called within a interrupt, but can be interrupted.
256 * The @ctor is run when new pages are allocated by the cache.
257 *
258 * The flags are
259 *
260 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
261 * to catch references to uninitialised memory.
262 *
263 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
264 * for buffer overruns.
265 *
266 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
267 * cacheline. This can be beneficial if you're counting cycles as closely
268 * as davem.
269 *
270 * Return: a pointer to the cache on success, NULL on failure.
271 */
272struct kmem_cache *
273kmem_cache_create_usercopy(const char *name,
274 unsigned int size, unsigned int align,
275 slab_flags_t flags,
276 unsigned int useroffset, unsigned int usersize,
277 void (*ctor)(void *))
278{
279 struct kmem_cache *s = NULL;
280 const char *cache_name;
281 int err;
282
283#ifdef CONFIG_SLUB_DEBUG
284 /*
285 * If no slab_debug was enabled globally, the static key is not yet
286 * enabled by setup_slub_debug(). Enable it if the cache is being
287 * created with any of the debugging flags passed explicitly.
288 * It's also possible that this is the first cache created with
289 * SLAB_STORE_USER and we should init stack_depot for it.
290 */
291 if (flags & SLAB_DEBUG_FLAGS)
292 static_branch_enable(&slub_debug_enabled);
293 if (flags & SLAB_STORE_USER)
294 stack_depot_init();
295#endif
296
297 mutex_lock(&slab_mutex);
298
299 err = kmem_cache_sanity_check(name, size);
300 if (err) {
301 goto out_unlock;
302 }
303
304 /* Refuse requests with allocator specific flags */
305 if (flags & ~SLAB_FLAGS_PERMITTED) {
306 err = -EINVAL;
307 goto out_unlock;
308 }
309
310 /*
311 * Some allocators will constraint the set of valid flags to a subset
312 * of all flags. We expect them to define CACHE_CREATE_MASK in this
313 * case, and we'll just provide them with a sanitized version of the
314 * passed flags.
315 */
316 flags &= CACHE_CREATE_MASK;
317
318 /* Fail closed on bad usersize of useroffset values. */
319 if (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) ||
320 WARN_ON(!usersize && useroffset) ||
321 WARN_ON(size < usersize || size - usersize < useroffset))
322 usersize = useroffset = 0;
323
324 if (!usersize)
325 s = __kmem_cache_alias(name, size, align, flags, ctor);
326 if (s)
327 goto out_unlock;
328
329 cache_name = kstrdup_const(name, GFP_KERNEL);
330 if (!cache_name) {
331 err = -ENOMEM;
332 goto out_unlock;
333 }
334
335 s = create_cache(cache_name, size,
336 calculate_alignment(flags, align, size),
337 flags, useroffset, usersize, ctor, NULL);
338 if (IS_ERR(s)) {
339 err = PTR_ERR(s);
340 kfree_const(cache_name);
341 }
342
343out_unlock:
344 mutex_unlock(&slab_mutex);
345
346 if (err) {
347 if (flags & SLAB_PANIC)
348 panic("%s: Failed to create slab '%s'. Error %d\n",
349 __func__, name, err);
350 else {
351 pr_warn("%s(%s) failed with error %d\n",
352 __func__, name, err);
353 dump_stack();
354 }
355 return NULL;
356 }
357 return s;
358}
359EXPORT_SYMBOL(kmem_cache_create_usercopy);
360
361/**
362 * kmem_cache_create - Create a cache.
363 * @name: A string which is used in /proc/slabinfo to identify this cache.
364 * @size: The size of objects to be created in this cache.
365 * @align: The required alignment for the objects.
366 * @flags: SLAB flags
367 * @ctor: A constructor for the objects.
368 *
369 * Cannot be called within a interrupt, but can be interrupted.
370 * The @ctor is run when new pages are allocated by the cache.
371 *
372 * The flags are
373 *
374 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
375 * to catch references to uninitialised memory.
376 *
377 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
378 * for buffer overruns.
379 *
380 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
381 * cacheline. This can be beneficial if you're counting cycles as closely
382 * as davem.
383 *
384 * Return: a pointer to the cache on success, NULL on failure.
385 */
386struct kmem_cache *
387kmem_cache_create(const char *name, unsigned int size, unsigned int align,
388 slab_flags_t flags, void (*ctor)(void *))
389{
390 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
391 ctor);
392}
393EXPORT_SYMBOL(kmem_cache_create);
394
395#ifdef SLAB_SUPPORTS_SYSFS
396/*
397 * For a given kmem_cache, kmem_cache_destroy() should only be called
398 * once or there will be a use-after-free problem. The actual deletion
399 * and release of the kobject does not need slab_mutex or cpu_hotplug_lock
400 * protection. So they are now done without holding those locks.
401 *
402 * Note that there will be a slight delay in the deletion of sysfs files
403 * if kmem_cache_release() is called indrectly from a work function.
404 */
405static void kmem_cache_release(struct kmem_cache *s)
406{
407 if (slab_state >= FULL) {
408 sysfs_slab_unlink(s);
409 sysfs_slab_release(s);
410 } else {
411 slab_kmem_cache_release(s);
412 }
413}
414#else
415static void kmem_cache_release(struct kmem_cache *s)
416{
417 slab_kmem_cache_release(s);
418}
419#endif
420
421static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
422{
423 LIST_HEAD(to_destroy);
424 struct kmem_cache *s, *s2;
425
426 /*
427 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
428 * @slab_caches_to_rcu_destroy list. The slab pages are freed
429 * through RCU and the associated kmem_cache are dereferenced
430 * while freeing the pages, so the kmem_caches should be freed only
431 * after the pending RCU operations are finished. As rcu_barrier()
432 * is a pretty slow operation, we batch all pending destructions
433 * asynchronously.
434 */
435 mutex_lock(&slab_mutex);
436 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
437 mutex_unlock(&slab_mutex);
438
439 if (list_empty(&to_destroy))
440 return;
441
442 rcu_barrier();
443
444 list_for_each_entry_safe(s, s2, &to_destroy, list) {
445 debugfs_slab_release(s);
446 kfence_shutdown_cache(s);
447 kmem_cache_release(s);
448 }
449}
450
451static int shutdown_cache(struct kmem_cache *s)
452{
453 /* free asan quarantined objects */
454 kasan_cache_shutdown(s);
455
456 if (__kmem_cache_shutdown(s) != 0)
457 return -EBUSY;
458
459 list_del(&s->list);
460
461 if (s->flags & SLAB_TYPESAFE_BY_RCU) {
462 list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
463 schedule_work(&slab_caches_to_rcu_destroy_work);
464 } else {
465 kfence_shutdown_cache(s);
466 debugfs_slab_release(s);
467 }
468
469 return 0;
470}
471
472void slab_kmem_cache_release(struct kmem_cache *s)
473{
474 __kmem_cache_release(s);
475 kfree_const(s->name);
476 kmem_cache_free(kmem_cache, s);
477}
478
479void kmem_cache_destroy(struct kmem_cache *s)
480{
481 int err = -EBUSY;
482 bool rcu_set;
483
484 if (unlikely(!s) || !kasan_check_byte(s))
485 return;
486
487 cpus_read_lock();
488 mutex_lock(&slab_mutex);
489
490 rcu_set = s->flags & SLAB_TYPESAFE_BY_RCU;
491
492 s->refcount--;
493 if (s->refcount)
494 goto out_unlock;
495
496 err = shutdown_cache(s);
497 WARN(err, "%s %s: Slab cache still has objects when called from %pS",
498 __func__, s->name, (void *)_RET_IP_);
499out_unlock:
500 mutex_unlock(&slab_mutex);
501 cpus_read_unlock();
502 if (!err && !rcu_set)
503 kmem_cache_release(s);
504}
505EXPORT_SYMBOL(kmem_cache_destroy);
506
507/**
508 * kmem_cache_shrink - Shrink a cache.
509 * @cachep: The cache to shrink.
510 *
511 * Releases as many slabs as possible for a cache.
512 * To help debugging, a zero exit status indicates all slabs were released.
513 *
514 * Return: %0 if all slabs were released, non-zero otherwise
515 */
516int kmem_cache_shrink(struct kmem_cache *cachep)
517{
518 kasan_cache_shrink(cachep);
519
520 return __kmem_cache_shrink(cachep);
521}
522EXPORT_SYMBOL(kmem_cache_shrink);
523
524bool slab_is_available(void)
525{
526 return slab_state >= UP;
527}
528
529#ifdef CONFIG_PRINTK
530static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
531{
532 if (__kfence_obj_info(kpp, object, slab))
533 return;
534 __kmem_obj_info(kpp, object, slab);
535}
536
537/**
538 * kmem_dump_obj - Print available slab provenance information
539 * @object: slab object for which to find provenance information.
540 *
541 * This function uses pr_cont(), so that the caller is expected to have
542 * printed out whatever preamble is appropriate. The provenance information
543 * depends on the type of object and on how much debugging is enabled.
544 * For a slab-cache object, the fact that it is a slab object is printed,
545 * and, if available, the slab name, return address, and stack trace from
546 * the allocation and last free path of that object.
547 *
548 * Return: %true if the pointer is to a not-yet-freed object from
549 * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
550 * is to an already-freed object, and %false otherwise.
551 */
552bool kmem_dump_obj(void *object)
553{
554 char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
555 int i;
556 struct slab *slab;
557 unsigned long ptroffset;
558 struct kmem_obj_info kp = { };
559
560 /* Some arches consider ZERO_SIZE_PTR to be a valid address. */
561 if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
562 return false;
563 slab = virt_to_slab(object);
564 if (!slab)
565 return false;
566
567 kmem_obj_info(&kp, object, slab);
568 if (kp.kp_slab_cache)
569 pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
570 else
571 pr_cont(" slab%s", cp);
572 if (is_kfence_address(object))
573 pr_cont(" (kfence)");
574 if (kp.kp_objp)
575 pr_cont(" start %px", kp.kp_objp);
576 if (kp.kp_data_offset)
577 pr_cont(" data offset %lu", kp.kp_data_offset);
578 if (kp.kp_objp) {
579 ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset;
580 pr_cont(" pointer offset %lu", ptroffset);
581 }
582 if (kp.kp_slab_cache && kp.kp_slab_cache->object_size)
583 pr_cont(" size %u", kp.kp_slab_cache->object_size);
584 if (kp.kp_ret)
585 pr_cont(" allocated at %pS\n", kp.kp_ret);
586 else
587 pr_cont("\n");
588 for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) {
589 if (!kp.kp_stack[i])
590 break;
591 pr_info(" %pS\n", kp.kp_stack[i]);
592 }
593
594 if (kp.kp_free_stack[0])
595 pr_cont(" Free path:\n");
596
597 for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
598 if (!kp.kp_free_stack[i])
599 break;
600 pr_info(" %pS\n", kp.kp_free_stack[i]);
601 }
602
603 return true;
604}
605EXPORT_SYMBOL_GPL(kmem_dump_obj);
606#endif
607
608/* Create a cache during boot when no slab services are available yet */
609void __init create_boot_cache(struct kmem_cache *s, const char *name,
610 unsigned int size, slab_flags_t flags,
611 unsigned int useroffset, unsigned int usersize)
612{
613 int err;
614 unsigned int align = ARCH_KMALLOC_MINALIGN;
615
616 s->name = name;
617 s->size = s->object_size = size;
618
619 /*
620 * For power of two sizes, guarantee natural alignment for kmalloc
621 * caches, regardless of SL*B debugging options.
622 */
623 if (is_power_of_2(size))
624 align = max(align, size);
625 s->align = calculate_alignment(flags, align, size);
626
627#ifdef CONFIG_HARDENED_USERCOPY
628 s->useroffset = useroffset;
629 s->usersize = usersize;
630#endif
631
632 err = __kmem_cache_create(s, flags);
633
634 if (err)
635 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
636 name, size, err);
637
638 s->refcount = -1; /* Exempt from merging for now */
639}
640
641static struct kmem_cache *__init create_kmalloc_cache(const char *name,
642 unsigned int size,
643 slab_flags_t flags)
644{
645 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
646
647 if (!s)
648 panic("Out of memory when creating slab %s\n", name);
649
650 create_boot_cache(s, name, size, flags | SLAB_KMALLOC, 0, size);
651 list_add(&s->list, &slab_caches);
652 s->refcount = 1;
653 return s;
654}
655
656struct kmem_cache *
657kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
658{ /* initialization for https://llvm.org/pr42570 */ };
659EXPORT_SYMBOL(kmalloc_caches);
660
661#ifdef CONFIG_RANDOM_KMALLOC_CACHES
662unsigned long random_kmalloc_seed __ro_after_init;
663EXPORT_SYMBOL(random_kmalloc_seed);
664#endif
665
666/*
667 * Conversion table for small slabs sizes / 8 to the index in the
668 * kmalloc array. This is necessary for slabs < 192 since we have non power
669 * of two cache sizes there. The size of larger slabs can be determined using
670 * fls.
671 */
672u8 kmalloc_size_index[24] __ro_after_init = {
673 3, /* 8 */
674 4, /* 16 */
675 5, /* 24 */
676 5, /* 32 */
677 6, /* 40 */
678 6, /* 48 */
679 6, /* 56 */
680 6, /* 64 */
681 1, /* 72 */
682 1, /* 80 */
683 1, /* 88 */
684 1, /* 96 */
685 7, /* 104 */
686 7, /* 112 */
687 7, /* 120 */
688 7, /* 128 */
689 2, /* 136 */
690 2, /* 144 */
691 2, /* 152 */
692 2, /* 160 */
693 2, /* 168 */
694 2, /* 176 */
695 2, /* 184 */
696 2 /* 192 */
697};
698
699size_t kmalloc_size_roundup(size_t size)
700{
701 if (size && size <= KMALLOC_MAX_CACHE_SIZE) {
702 /*
703 * The flags don't matter since size_index is common to all.
704 * Neither does the caller for just getting ->object_size.
705 */
706 return kmalloc_slab(size, GFP_KERNEL, 0)->object_size;
707 }
708
709 /* Above the smaller buckets, size is a multiple of page size. */
710 if (size && size <= KMALLOC_MAX_SIZE)
711 return PAGE_SIZE << get_order(size);
712
713 /*
714 * Return 'size' for 0 - kmalloc() returns ZERO_SIZE_PTR
715 * and very large size - kmalloc() may fail.
716 */
717 return size;
718
719}
720EXPORT_SYMBOL(kmalloc_size_roundup);
721
722#ifdef CONFIG_ZONE_DMA
723#define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz,
724#else
725#define KMALLOC_DMA_NAME(sz)
726#endif
727
728#ifdef CONFIG_MEMCG_KMEM
729#define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz,
730#else
731#define KMALLOC_CGROUP_NAME(sz)
732#endif
733
734#ifndef CONFIG_SLUB_TINY
735#define KMALLOC_RCL_NAME(sz) .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #sz,
736#else
737#define KMALLOC_RCL_NAME(sz)
738#endif
739
740#ifdef CONFIG_RANDOM_KMALLOC_CACHES
741#define __KMALLOC_RANDOM_CONCAT(a, b) a ## b
742#define KMALLOC_RANDOM_NAME(N, sz) __KMALLOC_RANDOM_CONCAT(KMA_RAND_, N)(sz)
743#define KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 1] = "kmalloc-rnd-01-" #sz,
744#define KMA_RAND_2(sz) KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 2] = "kmalloc-rnd-02-" #sz,
745#define KMA_RAND_3(sz) KMA_RAND_2(sz) .name[KMALLOC_RANDOM_START + 3] = "kmalloc-rnd-03-" #sz,
746#define KMA_RAND_4(sz) KMA_RAND_3(sz) .name[KMALLOC_RANDOM_START + 4] = "kmalloc-rnd-04-" #sz,
747#define KMA_RAND_5(sz) KMA_RAND_4(sz) .name[KMALLOC_RANDOM_START + 5] = "kmalloc-rnd-05-" #sz,
748#define KMA_RAND_6(sz) KMA_RAND_5(sz) .name[KMALLOC_RANDOM_START + 6] = "kmalloc-rnd-06-" #sz,
749#define KMA_RAND_7(sz) KMA_RAND_6(sz) .name[KMALLOC_RANDOM_START + 7] = "kmalloc-rnd-07-" #sz,
750#define KMA_RAND_8(sz) KMA_RAND_7(sz) .name[KMALLOC_RANDOM_START + 8] = "kmalloc-rnd-08-" #sz,
751#define KMA_RAND_9(sz) KMA_RAND_8(sz) .name[KMALLOC_RANDOM_START + 9] = "kmalloc-rnd-09-" #sz,
752#define KMA_RAND_10(sz) KMA_RAND_9(sz) .name[KMALLOC_RANDOM_START + 10] = "kmalloc-rnd-10-" #sz,
753#define KMA_RAND_11(sz) KMA_RAND_10(sz) .name[KMALLOC_RANDOM_START + 11] = "kmalloc-rnd-11-" #sz,
754#define KMA_RAND_12(sz) KMA_RAND_11(sz) .name[KMALLOC_RANDOM_START + 12] = "kmalloc-rnd-12-" #sz,
755#define KMA_RAND_13(sz) KMA_RAND_12(sz) .name[KMALLOC_RANDOM_START + 13] = "kmalloc-rnd-13-" #sz,
756#define KMA_RAND_14(sz) KMA_RAND_13(sz) .name[KMALLOC_RANDOM_START + 14] = "kmalloc-rnd-14-" #sz,
757#define KMA_RAND_15(sz) KMA_RAND_14(sz) .name[KMALLOC_RANDOM_START + 15] = "kmalloc-rnd-15-" #sz,
758#else // CONFIG_RANDOM_KMALLOC_CACHES
759#define KMALLOC_RANDOM_NAME(N, sz)
760#endif
761
762#define INIT_KMALLOC_INFO(__size, __short_size) \
763{ \
764 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
765 KMALLOC_RCL_NAME(__short_size) \
766 KMALLOC_CGROUP_NAME(__short_size) \
767 KMALLOC_DMA_NAME(__short_size) \
768 KMALLOC_RANDOM_NAME(RANDOM_KMALLOC_CACHES_NR, __short_size) \
769 .size = __size, \
770}
771
772/*
773 * kmalloc_info[] is to make slab_debug=,kmalloc-xx option work at boot time.
774 * kmalloc_index() supports up to 2^21=2MB, so the final entry of the table is
775 * kmalloc-2M.
776 */
777const struct kmalloc_info_struct kmalloc_info[] __initconst = {
778 INIT_KMALLOC_INFO(0, 0),
779 INIT_KMALLOC_INFO(96, 96),
780 INIT_KMALLOC_INFO(192, 192),
781 INIT_KMALLOC_INFO(8, 8),
782 INIT_KMALLOC_INFO(16, 16),
783 INIT_KMALLOC_INFO(32, 32),
784 INIT_KMALLOC_INFO(64, 64),
785 INIT_KMALLOC_INFO(128, 128),
786 INIT_KMALLOC_INFO(256, 256),
787 INIT_KMALLOC_INFO(512, 512),
788 INIT_KMALLOC_INFO(1024, 1k),
789 INIT_KMALLOC_INFO(2048, 2k),
790 INIT_KMALLOC_INFO(4096, 4k),
791 INIT_KMALLOC_INFO(8192, 8k),
792 INIT_KMALLOC_INFO(16384, 16k),
793 INIT_KMALLOC_INFO(32768, 32k),
794 INIT_KMALLOC_INFO(65536, 64k),
795 INIT_KMALLOC_INFO(131072, 128k),
796 INIT_KMALLOC_INFO(262144, 256k),
797 INIT_KMALLOC_INFO(524288, 512k),
798 INIT_KMALLOC_INFO(1048576, 1M),
799 INIT_KMALLOC_INFO(2097152, 2M)
800};
801
802/*
803 * Patch up the size_index table if we have strange large alignment
804 * requirements for the kmalloc array. This is only the case for
805 * MIPS it seems. The standard arches will not generate any code here.
806 *
807 * Largest permitted alignment is 256 bytes due to the way we
808 * handle the index determination for the smaller caches.
809 *
810 * Make sure that nothing crazy happens if someone starts tinkering
811 * around with ARCH_KMALLOC_MINALIGN
812 */
813void __init setup_kmalloc_cache_index_table(void)
814{
815 unsigned int i;
816
817 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
818 !is_power_of_2(KMALLOC_MIN_SIZE));
819
820 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
821 unsigned int elem = size_index_elem(i);
822
823 if (elem >= ARRAY_SIZE(kmalloc_size_index))
824 break;
825 kmalloc_size_index[elem] = KMALLOC_SHIFT_LOW;
826 }
827
828 if (KMALLOC_MIN_SIZE >= 64) {
829 /*
830 * The 96 byte sized cache is not used if the alignment
831 * is 64 byte.
832 */
833 for (i = 64 + 8; i <= 96; i += 8)
834 kmalloc_size_index[size_index_elem(i)] = 7;
835
836 }
837
838 if (KMALLOC_MIN_SIZE >= 128) {
839 /*
840 * The 192 byte sized cache is not used if the alignment
841 * is 128 byte. Redirect kmalloc to use the 256 byte cache
842 * instead.
843 */
844 for (i = 128 + 8; i <= 192; i += 8)
845 kmalloc_size_index[size_index_elem(i)] = 8;
846 }
847}
848
849static unsigned int __kmalloc_minalign(void)
850{
851 unsigned int minalign = dma_get_cache_alignment();
852
853 if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) &&
854 is_swiotlb_allocated())
855 minalign = ARCH_KMALLOC_MINALIGN;
856
857 return max(minalign, arch_slab_minalign());
858}
859
860static void __init
861new_kmalloc_cache(int idx, enum kmalloc_cache_type type)
862{
863 slab_flags_t flags = 0;
864 unsigned int minalign = __kmalloc_minalign();
865 unsigned int aligned_size = kmalloc_info[idx].size;
866 int aligned_idx = idx;
867
868 if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) {
869 flags |= SLAB_RECLAIM_ACCOUNT;
870 } else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_CGROUP)) {
871 if (mem_cgroup_kmem_disabled()) {
872 kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx];
873 return;
874 }
875 flags |= SLAB_ACCOUNT;
876 } else if (IS_ENABLED(CONFIG_ZONE_DMA) && (type == KMALLOC_DMA)) {
877 flags |= SLAB_CACHE_DMA;
878 }
879
880#ifdef CONFIG_RANDOM_KMALLOC_CACHES
881 if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END)
882 flags |= SLAB_NO_MERGE;
883#endif
884
885 /*
886 * If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
887 * KMALLOC_NORMAL caches.
888 */
889 if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL))
890 flags |= SLAB_NO_MERGE;
891
892 if (minalign > ARCH_KMALLOC_MINALIGN) {
893 aligned_size = ALIGN(aligned_size, minalign);
894 aligned_idx = __kmalloc_index(aligned_size, false);
895 }
896
897 if (!kmalloc_caches[type][aligned_idx])
898 kmalloc_caches[type][aligned_idx] = create_kmalloc_cache(
899 kmalloc_info[aligned_idx].name[type],
900 aligned_size, flags);
901 if (idx != aligned_idx)
902 kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx];
903}
904
905/*
906 * Create the kmalloc array. Some of the regular kmalloc arrays
907 * may already have been created because they were needed to
908 * enable allocations for slab creation.
909 */
910void __init create_kmalloc_caches(void)
911{
912 int i;
913 enum kmalloc_cache_type type;
914
915 /*
916 * Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined
917 */
918 for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) {
919 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
920 if (!kmalloc_caches[type][i])
921 new_kmalloc_cache(i, type);
922
923 /*
924 * Caches that are not of the two-to-the-power-of size.
925 * These have to be created immediately after the
926 * earlier power of two caches
927 */
928 if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
929 !kmalloc_caches[type][1])
930 new_kmalloc_cache(1, type);
931 if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
932 !kmalloc_caches[type][2])
933 new_kmalloc_cache(2, type);
934 }
935 }
936#ifdef CONFIG_RANDOM_KMALLOC_CACHES
937 random_kmalloc_seed = get_random_u64();
938#endif
939
940 /* Kmalloc array is now usable */
941 slab_state = UP;
942}
943
944/**
945 * __ksize -- Report full size of underlying allocation
946 * @object: pointer to the object
947 *
948 * This should only be used internally to query the true size of allocations.
949 * It is not meant to be a way to discover the usable size of an allocation
950 * after the fact. Instead, use kmalloc_size_roundup(). Using memory beyond
951 * the originally requested allocation size may trigger KASAN, UBSAN_BOUNDS,
952 * and/or FORTIFY_SOURCE.
953 *
954 * Return: size of the actual memory used by @object in bytes
955 */
956size_t __ksize(const void *object)
957{
958 struct folio *folio;
959
960 if (unlikely(object == ZERO_SIZE_PTR))
961 return 0;
962
963 folio = virt_to_folio(object);
964
965 if (unlikely(!folio_test_slab(folio))) {
966 if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE))
967 return 0;
968 if (WARN_ON(object != folio_address(folio)))
969 return 0;
970 return folio_size(folio);
971 }
972
973#ifdef CONFIG_SLUB_DEBUG
974 skip_orig_size_check(folio_slab(folio)->slab_cache, object);
975#endif
976
977 return slab_ksize(folio_slab(folio)->slab_cache);
978}
979
980gfp_t kmalloc_fix_flags(gfp_t flags)
981{
982 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
983
984 flags &= ~GFP_SLAB_BUG_MASK;
985 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
986 invalid_mask, &invalid_mask, flags, &flags);
987 dump_stack();
988
989 return flags;
990}
991
992#ifdef CONFIG_SLAB_FREELIST_RANDOM
993/* Randomize a generic freelist */
994static void freelist_randomize(unsigned int *list,
995 unsigned int count)
996{
997 unsigned int rand;
998 unsigned int i;
999
1000 for (i = 0; i < count; i++)
1001 list[i] = i;
1002
1003 /* Fisher-Yates shuffle */
1004 for (i = count - 1; i > 0; i--) {
1005 rand = get_random_u32_below(i + 1);
1006 swap(list[i], list[rand]);
1007 }
1008}
1009
1010/* Create a random sequence per cache */
1011int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
1012 gfp_t gfp)
1013{
1014
1015 if (count < 2 || cachep->random_seq)
1016 return 0;
1017
1018 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
1019 if (!cachep->random_seq)
1020 return -ENOMEM;
1021
1022 freelist_randomize(cachep->random_seq, count);
1023 return 0;
1024}
1025
1026/* Destroy the per-cache random freelist sequence */
1027void cache_random_seq_destroy(struct kmem_cache *cachep)
1028{
1029 kfree(cachep->random_seq);
1030 cachep->random_seq = NULL;
1031}
1032#endif /* CONFIG_SLAB_FREELIST_RANDOM */
1033
1034#ifdef CONFIG_SLUB_DEBUG
1035#define SLABINFO_RIGHTS (0400)
1036
1037static void print_slabinfo_header(struct seq_file *m)
1038{
1039 /*
1040 * Output format version, so at least we can change it
1041 * without _too_ many complaints.
1042 */
1043 seq_puts(m, "slabinfo - version: 2.1\n");
1044 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1045 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
1046 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1047 seq_putc(m, '\n');
1048}
1049
1050static void *slab_start(struct seq_file *m, loff_t *pos)
1051{
1052 mutex_lock(&slab_mutex);
1053 return seq_list_start(&slab_caches, *pos);
1054}
1055
1056static void *slab_next(struct seq_file *m, void *p, loff_t *pos)
1057{
1058 return seq_list_next(p, &slab_caches, pos);
1059}
1060
1061static void slab_stop(struct seq_file *m, void *p)
1062{
1063 mutex_unlock(&slab_mutex);
1064}
1065
1066static void cache_show(struct kmem_cache *s, struct seq_file *m)
1067{
1068 struct slabinfo sinfo;
1069
1070 memset(&sinfo, 0, sizeof(sinfo));
1071 get_slabinfo(s, &sinfo);
1072
1073 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
1074 s->name, sinfo.active_objs, sinfo.num_objs, s->size,
1075 sinfo.objects_per_slab, (1 << sinfo.cache_order));
1076
1077 seq_printf(m, " : tunables %4u %4u %4u",
1078 sinfo.limit, sinfo.batchcount, sinfo.shared);
1079 seq_printf(m, " : slabdata %6lu %6lu %6lu",
1080 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
1081 slabinfo_show_stats(m, s);
1082 seq_putc(m, '\n');
1083}
1084
1085static int slab_show(struct seq_file *m, void *p)
1086{
1087 struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
1088
1089 if (p == slab_caches.next)
1090 print_slabinfo_header(m);
1091 cache_show(s, m);
1092 return 0;
1093}
1094
1095void dump_unreclaimable_slab(void)
1096{
1097 struct kmem_cache *s;
1098 struct slabinfo sinfo;
1099
1100 /*
1101 * Here acquiring slab_mutex is risky since we don't prefer to get
1102 * sleep in oom path. But, without mutex hold, it may introduce a
1103 * risk of crash.
1104 * Use mutex_trylock to protect the list traverse, dump nothing
1105 * without acquiring the mutex.
1106 */
1107 if (!mutex_trylock(&slab_mutex)) {
1108 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1109 return;
1110 }
1111
1112 pr_info("Unreclaimable slab info:\n");
1113 pr_info("Name Used Total\n");
1114
1115 list_for_each_entry(s, &slab_caches, list) {
1116 if (s->flags & SLAB_RECLAIM_ACCOUNT)
1117 continue;
1118
1119 get_slabinfo(s, &sinfo);
1120
1121 if (sinfo.num_objs > 0)
1122 pr_info("%-17s %10luKB %10luKB\n", s->name,
1123 (sinfo.active_objs * s->size) / 1024,
1124 (sinfo.num_objs * s->size) / 1024);
1125 }
1126 mutex_unlock(&slab_mutex);
1127}
1128
1129/*
1130 * slabinfo_op - iterator that generates /proc/slabinfo
1131 *
1132 * Output layout:
1133 * cache-name
1134 * num-active-objs
1135 * total-objs
1136 * object size
1137 * num-active-slabs
1138 * total-slabs
1139 * num-pages-per-slab
1140 * + further values on SMP and with statistics enabled
1141 */
1142static const struct seq_operations slabinfo_op = {
1143 .start = slab_start,
1144 .next = slab_next,
1145 .stop = slab_stop,
1146 .show = slab_show,
1147};
1148
1149static int slabinfo_open(struct inode *inode, struct file *file)
1150{
1151 return seq_open(file, &slabinfo_op);
1152}
1153
1154static const struct proc_ops slabinfo_proc_ops = {
1155 .proc_flags = PROC_ENTRY_PERMANENT,
1156 .proc_open = slabinfo_open,
1157 .proc_read = seq_read,
1158 .proc_write = slabinfo_write,
1159 .proc_lseek = seq_lseek,
1160 .proc_release = seq_release,
1161};
1162
1163static int __init slab_proc_init(void)
1164{
1165 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1166 return 0;
1167}
1168module_init(slab_proc_init);
1169
1170#endif /* CONFIG_SLUB_DEBUG */
1171
1172static __always_inline __realloc_size(2) void *
1173__do_krealloc(const void *p, size_t new_size, gfp_t flags)
1174{
1175 void *ret;
1176 size_t ks;
1177
1178 /* Check for double-free before calling ksize. */
1179 if (likely(!ZERO_OR_NULL_PTR(p))) {
1180 if (!kasan_check_byte(p))
1181 return NULL;
1182 ks = ksize(p);
1183 } else
1184 ks = 0;
1185
1186 /* If the object still fits, repoison it precisely. */
1187 if (ks >= new_size) {
1188 p = kasan_krealloc((void *)p, new_size, flags);
1189 return (void *)p;
1190 }
1191
1192 ret = kmalloc_track_caller(new_size, flags);
1193 if (ret && p) {
1194 /* Disable KASAN checks as the object's redzone is accessed. */
1195 kasan_disable_current();
1196 memcpy(ret, kasan_reset_tag(p), ks);
1197 kasan_enable_current();
1198 }
1199
1200 return ret;
1201}
1202
1203/**
1204 * krealloc - reallocate memory. The contents will remain unchanged.
1205 * @p: object to reallocate memory for.
1206 * @new_size: how many bytes of memory are required.
1207 * @flags: the type of memory to allocate.
1208 *
1209 * The contents of the object pointed to are preserved up to the
1210 * lesser of the new and old sizes (__GFP_ZERO flag is effectively ignored).
1211 * If @p is %NULL, krealloc() behaves exactly like kmalloc(). If @new_size
1212 * is 0 and @p is not a %NULL pointer, the object pointed to is freed.
1213 *
1214 * Return: pointer to the allocated memory or %NULL in case of error
1215 */
1216void *krealloc(const void *p, size_t new_size, gfp_t flags)
1217{
1218 void *ret;
1219
1220 if (unlikely(!new_size)) {
1221 kfree(p);
1222 return ZERO_SIZE_PTR;
1223 }
1224
1225 ret = __do_krealloc(p, new_size, flags);
1226 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
1227 kfree(p);
1228
1229 return ret;
1230}
1231EXPORT_SYMBOL(krealloc);
1232
1233/**
1234 * kfree_sensitive - Clear sensitive information in memory before freeing
1235 * @p: object to free memory of
1236 *
1237 * The memory of the object @p points to is zeroed before freed.
1238 * If @p is %NULL, kfree_sensitive() does nothing.
1239 *
1240 * Note: this function zeroes the whole allocated buffer which can be a good
1241 * deal bigger than the requested buffer size passed to kmalloc(). So be
1242 * careful when using this function in performance sensitive code.
1243 */
1244void kfree_sensitive(const void *p)
1245{
1246 size_t ks;
1247 void *mem = (void *)p;
1248
1249 ks = ksize(mem);
1250 if (ks) {
1251 kasan_unpoison_range(mem, ks);
1252 memzero_explicit(mem, ks);
1253 }
1254 kfree(mem);
1255}
1256EXPORT_SYMBOL(kfree_sensitive);
1257
1258size_t ksize(const void *objp)
1259{
1260 /*
1261 * We need to first check that the pointer to the object is valid.
1262 * The KASAN report printed from ksize() is more useful, then when
1263 * it's printed later when the behaviour could be undefined due to
1264 * a potential use-after-free or double-free.
1265 *
1266 * We use kasan_check_byte(), which is supported for the hardware
1267 * tag-based KASAN mode, unlike kasan_check_read/write().
1268 *
1269 * If the pointed to memory is invalid, we return 0 to avoid users of
1270 * ksize() writing to and potentially corrupting the memory region.
1271 *
1272 * We want to perform the check before __ksize(), to avoid potentially
1273 * crashing in __ksize() due to accessing invalid metadata.
1274 */
1275 if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
1276 return 0;
1277
1278 return kfence_ksize(objp) ?: __ksize(objp);
1279}
1280EXPORT_SYMBOL(ksize);
1281
1282/* Tracepoints definitions. */
1283EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1284EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1285EXPORT_TRACEPOINT_SYMBOL(kfree);
1286EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1287