1 // SPDX-License-Identifier: GPL-2.0
3 * Slab allocator functions that are independent of the allocator strategy
5 * (C) 2012 Christoph Lameter <cl@linux.com>
7 #include <linux/slab.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/module.h>
16 #include <linux/cpu.h>
17 #include <linux/uaccess.h>
18 #include <linux/seq_file.h>
19 #include <linux/proc_fs.h>
20 #include <linux/debugfs.h>
21 #include <asm/cacheflush.h>
22 #include <asm/tlbflush.h>
24 #include <linux/memcontrol.h>
26 #define CREATE_TRACE_POINTS
27 #include <trace/events/kmem.h>
31 enum slab_state slab_state;
32 LIST_HEAD(slab_caches);
33 DEFINE_MUTEX(slab_mutex);
34 struct kmem_cache *kmem_cache;
36 #ifdef CONFIG_HARDENED_USERCOPY
37 bool usercopy_fallback __ro_after_init =
38 IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
39 module_param(usercopy_fallback, bool, 0400);
40 MODULE_PARM_DESC(usercopy_fallback,
41 "WARN instead of reject usercopy whitelist violations");
44 static LIST_HEAD(slab_caches_to_rcu_destroy);
45 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
46 static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
47 slab_caches_to_rcu_destroy_workfn);
50 * Set of flags that will prevent slab merging
52 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
53 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
54 SLAB_FAILSLAB | SLAB_KASAN)
56 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
57 SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
60 * Merge control. If this is set then no merging of slab caches will occur.
62 static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
64 static int __init setup_slab_nomerge(char *str)
71 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
74 __setup("slab_nomerge", setup_slab_nomerge);
77 * Determine the size of a slab object
79 unsigned int kmem_cache_size(struct kmem_cache *s)
81 return s->object_size;
83 EXPORT_SYMBOL(kmem_cache_size);
85 #ifdef CONFIG_DEBUG_VM
86 static int kmem_cache_sanity_check(const char *name, unsigned int size)
88 if (!name || in_interrupt() || size < sizeof(void *) ||
89 size > KMALLOC_MAX_SIZE) {
90 pr_err("kmem_cache_create(%s) integrity check failed\n", name);
94 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
98 static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
104 void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
108 for (i = 0; i < nr; i++) {
110 kmem_cache_free(s, p[i]);
116 int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
121 for (i = 0; i < nr; i++) {
122 void *x = p[i] = kmem_cache_alloc(s, flags);
124 __kmem_cache_free_bulk(s, i, p);
131 #ifdef CONFIG_MEMCG_KMEM
133 LIST_HEAD(slab_root_caches);
134 static DEFINE_SPINLOCK(memcg_kmem_wq_lock);
136 static void kmemcg_cache_shutdown(struct percpu_ref *percpu_ref);
138 void slab_init_memcg_params(struct kmem_cache *s)
140 s->memcg_params.root_cache = NULL;
141 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL);
142 INIT_LIST_HEAD(&s->memcg_params.children);
143 s->memcg_params.dying = false;
146 static int init_memcg_params(struct kmem_cache *s,
147 struct kmem_cache *root_cache)
149 struct memcg_cache_array *arr;
152 int ret = percpu_ref_init(&s->memcg_params.refcnt,
153 kmemcg_cache_shutdown,
158 s->memcg_params.root_cache = root_cache;
159 INIT_LIST_HEAD(&s->memcg_params.children_node);
160 INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node);
164 slab_init_memcg_params(s);
166 if (!memcg_nr_cache_ids)
169 arr = kvzalloc(sizeof(struct memcg_cache_array) +
170 memcg_nr_cache_ids * sizeof(void *),
175 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr);
179 static void destroy_memcg_params(struct kmem_cache *s)
181 if (is_root_cache(s)) {
182 kvfree(rcu_access_pointer(s->memcg_params.memcg_caches));
184 mem_cgroup_put(s->memcg_params.memcg);
185 WRITE_ONCE(s->memcg_params.memcg, NULL);
186 percpu_ref_exit(&s->memcg_params.refcnt);
190 static void free_memcg_params(struct rcu_head *rcu)
192 struct memcg_cache_array *old;
194 old = container_of(rcu, struct memcg_cache_array, rcu);
198 static int update_memcg_params(struct kmem_cache *s, int new_array_size)
200 struct memcg_cache_array *old, *new;
202 new = kvzalloc(sizeof(struct memcg_cache_array) +
203 new_array_size * sizeof(void *), GFP_KERNEL);
207 old = rcu_dereference_protected(s->memcg_params.memcg_caches,
208 lockdep_is_held(&slab_mutex));
210 memcpy(new->entries, old->entries,
211 memcg_nr_cache_ids * sizeof(void *));
213 rcu_assign_pointer(s->memcg_params.memcg_caches, new);
215 call_rcu(&old->rcu, free_memcg_params);
219 int memcg_update_all_caches(int num_memcgs)
221 struct kmem_cache *s;
224 mutex_lock(&slab_mutex);
225 list_for_each_entry(s, &slab_root_caches, root_caches_node) {
226 ret = update_memcg_params(s, num_memcgs);
228 * Instead of freeing the memory, we'll just leave the caches
229 * up to this point in an updated state.
234 mutex_unlock(&slab_mutex);
238 void memcg_link_cache(struct kmem_cache *s, struct mem_cgroup *memcg)
240 if (is_root_cache(s)) {
241 list_add(&s->root_caches_node, &slab_root_caches);
243 css_get(&memcg->css);
244 s->memcg_params.memcg = memcg;
245 list_add(&s->memcg_params.children_node,
246 &s->memcg_params.root_cache->memcg_params.children);
247 list_add(&s->memcg_params.kmem_caches_node,
248 &s->memcg_params.memcg->kmem_caches);
252 static void memcg_unlink_cache(struct kmem_cache *s)
254 if (is_root_cache(s)) {
255 list_del(&s->root_caches_node);
257 list_del(&s->memcg_params.children_node);
258 list_del(&s->memcg_params.kmem_caches_node);
262 static inline int init_memcg_params(struct kmem_cache *s,
263 struct kmem_cache *root_cache)
268 static inline void destroy_memcg_params(struct kmem_cache *s)
272 static inline void memcg_unlink_cache(struct kmem_cache *s)
275 #endif /* CONFIG_MEMCG_KMEM */
278 * Figure out what the alignment of the objects will be given a set of
279 * flags, a user specified alignment and the size of the objects.
281 static unsigned int calculate_alignment(slab_flags_t flags,
282 unsigned int align, unsigned int size)
285 * If the user wants hardware cache aligned objects then follow that
286 * suggestion if the object is sufficiently large.
288 * The hardware cache alignment cannot override the specified
289 * alignment though. If that is greater then use it.
291 if (flags & SLAB_HWCACHE_ALIGN) {
294 ralign = cache_line_size();
295 while (size <= ralign / 2)
297 align = max(align, ralign);
300 if (align < ARCH_SLAB_MINALIGN)
301 align = ARCH_SLAB_MINALIGN;
303 return ALIGN(align, sizeof(void *));
307 * Find a mergeable slab cache
309 int slab_unmergeable(struct kmem_cache *s)
311 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
314 if (!is_root_cache(s))
324 * We may have set a slab to be unmergeable during bootstrap.
329 #ifdef CONFIG_MEMCG_KMEM
331 * Skip the dying kmem_cache.
333 if (s->memcg_params.dying)
340 struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
341 slab_flags_t flags, const char *name, void (*ctor)(void *))
343 struct kmem_cache *s;
351 size = ALIGN(size, sizeof(void *));
352 align = calculate_alignment(flags, align, size);
353 size = ALIGN(size, align);
354 flags = kmem_cache_flags(size, flags, name, NULL);
356 if (flags & SLAB_NEVER_MERGE)
359 list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) {
360 if (slab_unmergeable(s))
366 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
369 * Check if alignment is compatible.
370 * Courtesy of Adrian Drzewiecki
372 if ((s->size & ~(align - 1)) != s->size)
375 if (s->size - size >= sizeof(void *))
378 if (IS_ENABLED(CONFIG_SLAB) && align &&
379 (align > s->align || s->align % align))
387 static struct kmem_cache *create_cache(const char *name,
388 unsigned int object_size, unsigned int align,
389 slab_flags_t flags, unsigned int useroffset,
390 unsigned int usersize, void (*ctor)(void *),
391 struct mem_cgroup *memcg, struct kmem_cache *root_cache)
393 struct kmem_cache *s;
396 if (WARN_ON(useroffset + usersize > object_size))
397 useroffset = usersize = 0;
400 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
405 s->size = s->object_size = object_size;
408 s->useroffset = useroffset;
409 s->usersize = usersize;
411 err = init_memcg_params(s, root_cache);
415 err = __kmem_cache_create(s, flags);
420 list_add(&s->list, &slab_caches);
421 memcg_link_cache(s, memcg);
428 destroy_memcg_params(s);
429 kmem_cache_free(kmem_cache, s);
434 * kmem_cache_create_usercopy - Create a cache with a region suitable
435 * for copying to userspace
436 * @name: A string which is used in /proc/slabinfo to identify this cache.
437 * @size: The size of objects to be created in this cache.
438 * @align: The required alignment for the objects.
440 * @useroffset: Usercopy region offset
441 * @usersize: Usercopy region size
442 * @ctor: A constructor for the objects.
444 * Cannot be called within a interrupt, but can be interrupted.
445 * The @ctor is run when new pages are allocated by the cache.
449 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
450 * to catch references to uninitialised memory.
452 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
453 * for buffer overruns.
455 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
456 * cacheline. This can be beneficial if you're counting cycles as closely
459 * Return: a pointer to the cache on success, NULL on failure.
462 kmem_cache_create_usercopy(const char *name,
463 unsigned int size, unsigned int align,
465 unsigned int useroffset, unsigned int usersize,
466 void (*ctor)(void *))
468 struct kmem_cache *s = NULL;
469 const char *cache_name;
474 memcg_get_cache_ids();
476 mutex_lock(&slab_mutex);
478 err = kmem_cache_sanity_check(name, size);
483 /* Refuse requests with allocator specific flags */
484 if (flags & ~SLAB_FLAGS_PERMITTED) {
490 * Some allocators will constraint the set of valid flags to a subset
491 * of all flags. We expect them to define CACHE_CREATE_MASK in this
492 * case, and we'll just provide them with a sanitized version of the
495 flags &= CACHE_CREATE_MASK;
497 /* Fail closed on bad usersize of useroffset values. */
498 if (WARN_ON(!usersize && useroffset) ||
499 WARN_ON(size < usersize || size - usersize < useroffset))
500 usersize = useroffset = 0;
503 s = __kmem_cache_alias(name, size, align, flags, ctor);
507 cache_name = kstrdup_const(name, GFP_KERNEL);
513 s = create_cache(cache_name, size,
514 calculate_alignment(flags, align, size),
515 flags, useroffset, usersize, ctor, NULL, NULL);
518 kfree_const(cache_name);
522 mutex_unlock(&slab_mutex);
524 memcg_put_cache_ids();
529 if (flags & SLAB_PANIC)
530 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
533 pr_warn("kmem_cache_create(%s) failed with error %d\n",
541 EXPORT_SYMBOL(kmem_cache_create_usercopy);
544 * kmem_cache_create - Create a cache.
545 * @name: A string which is used in /proc/slabinfo to identify this cache.
546 * @size: The size of objects to be created in this cache.
547 * @align: The required alignment for the objects.
549 * @ctor: A constructor for the objects.
551 * Cannot be called within a interrupt, but can be interrupted.
552 * The @ctor is run when new pages are allocated by the cache.
556 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
557 * to catch references to uninitialised memory.
559 * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
560 * for buffer overruns.
562 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
563 * cacheline. This can be beneficial if you're counting cycles as closely
566 * Return: a pointer to the cache on success, NULL on failure.
569 kmem_cache_create(const char *name, unsigned int size, unsigned int align,
570 slab_flags_t flags, void (*ctor)(void *))
572 return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
575 EXPORT_SYMBOL(kmem_cache_create);
577 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
579 LIST_HEAD(to_destroy);
580 struct kmem_cache *s, *s2;
583 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
584 * @slab_caches_to_rcu_destroy list. The slab pages are freed
585 * through RCU and and the associated kmem_cache are dereferenced
586 * while freeing the pages, so the kmem_caches should be freed only
587 * after the pending RCU operations are finished. As rcu_barrier()
588 * is a pretty slow operation, we batch all pending destructions
591 mutex_lock(&slab_mutex);
592 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
593 mutex_unlock(&slab_mutex);
595 if (list_empty(&to_destroy))
600 list_for_each_entry_safe(s, s2, &to_destroy, list) {
601 #ifdef SLAB_SUPPORTS_SYSFS
602 sysfs_slab_release(s);
604 slab_kmem_cache_release(s);
609 static int shutdown_cache(struct kmem_cache *s)
611 /* free asan quarantined objects */
612 kasan_cache_shutdown(s);
614 if (__kmem_cache_shutdown(s) != 0)
617 memcg_unlink_cache(s);
620 if (s->flags & SLAB_TYPESAFE_BY_RCU) {
621 #ifdef SLAB_SUPPORTS_SYSFS
622 sysfs_slab_unlink(s);
624 list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
625 schedule_work(&slab_caches_to_rcu_destroy_work);
627 #ifdef SLAB_SUPPORTS_SYSFS
628 sysfs_slab_unlink(s);
629 sysfs_slab_release(s);
631 slab_kmem_cache_release(s);
638 #ifdef CONFIG_MEMCG_KMEM
640 * memcg_create_kmem_cache - Create a cache for a memory cgroup.
641 * @memcg: The memory cgroup the new cache is for.
642 * @root_cache: The parent of the new cache.
644 * This function attempts to create a kmem cache that will serve allocation
645 * requests going from @memcg to @root_cache. The new cache inherits properties
648 void memcg_create_kmem_cache(struct mem_cgroup *memcg,
649 struct kmem_cache *root_cache)
651 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */
652 struct cgroup_subsys_state *css = &memcg->css;
653 struct memcg_cache_array *arr;
654 struct kmem_cache *s = NULL;
661 mutex_lock(&slab_mutex);
664 * The memory cgroup could have been offlined while the cache
665 * creation work was pending.
667 if (memcg->kmem_state != KMEM_ONLINE)
670 idx = memcg_cache_id(memcg);
671 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches,
672 lockdep_is_held(&slab_mutex));
675 * Since per-memcg caches are created asynchronously on first
676 * allocation (see memcg_kmem_get_cache()), several threads can try to
677 * create the same cache, but only one of them may succeed.
679 if (arr->entries[idx])
682 cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf));
683 cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name,
684 css->serial_nr, memcg_name_buf);
688 s = create_cache(cache_name, root_cache->object_size,
690 root_cache->flags & CACHE_CREATE_MASK,
691 root_cache->useroffset, root_cache->usersize,
692 root_cache->ctor, memcg, root_cache);
694 * If we could not create a memcg cache, do not complain, because
695 * that's not critical at all as we can always proceed with the root
704 * Since readers won't lock (see memcg_kmem_get_cache()), we need a
705 * barrier here to ensure nobody will see the kmem_cache partially
709 arr->entries[idx] = s;
712 mutex_unlock(&slab_mutex);
718 static void kmemcg_workfn(struct work_struct *work)
720 struct kmem_cache *s = container_of(work, struct kmem_cache,
726 mutex_lock(&slab_mutex);
727 s->memcg_params.work_fn(s);
728 mutex_unlock(&slab_mutex);
734 static void kmemcg_rcufn(struct rcu_head *head)
736 struct kmem_cache *s = container_of(head, struct kmem_cache,
737 memcg_params.rcu_head);
740 * We need to grab blocking locks. Bounce to ->work. The
741 * work item shares the space with the RCU head and can't be
742 * initialized earlier.
744 INIT_WORK(&s->memcg_params.work, kmemcg_workfn);
745 queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
748 static void kmemcg_cache_shutdown_fn(struct kmem_cache *s)
750 WARN_ON(shutdown_cache(s));
753 static void kmemcg_cache_shutdown(struct percpu_ref *percpu_ref)
755 struct kmem_cache *s = container_of(percpu_ref, struct kmem_cache,
756 memcg_params.refcnt);
759 spin_lock_irqsave(&memcg_kmem_wq_lock, flags);
760 if (s->memcg_params.root_cache->memcg_params.dying)
763 s->memcg_params.work_fn = kmemcg_cache_shutdown_fn;
764 INIT_WORK(&s->memcg_params.work, kmemcg_workfn);
765 queue_work(memcg_kmem_cache_wq, &s->memcg_params.work);
768 spin_unlock_irqrestore(&memcg_kmem_wq_lock, flags);
771 static void kmemcg_cache_deactivate_after_rcu(struct kmem_cache *s)
773 __kmemcg_cache_deactivate_after_rcu(s);
774 percpu_ref_kill(&s->memcg_params.refcnt);
777 static void kmemcg_cache_deactivate(struct kmem_cache *s)
779 if (WARN_ON_ONCE(is_root_cache(s)))
782 __kmemcg_cache_deactivate(s);
783 s->flags |= SLAB_DEACTIVATED;
786 * memcg_kmem_wq_lock is used to synchronize memcg_params.dying
787 * flag and make sure that no new kmem_cache deactivation tasks
788 * are queued (see flush_memcg_workqueue() ).
790 spin_lock_irq(&memcg_kmem_wq_lock);
791 if (s->memcg_params.root_cache->memcg_params.dying)
794 s->memcg_params.work_fn = kmemcg_cache_deactivate_after_rcu;
795 call_rcu(&s->memcg_params.rcu_head, kmemcg_rcufn);
797 spin_unlock_irq(&memcg_kmem_wq_lock);
800 void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg,
801 struct mem_cgroup *parent)
804 struct memcg_cache_array *arr;
805 struct kmem_cache *s, *c;
806 unsigned int nr_reparented;
808 idx = memcg_cache_id(memcg);
813 mutex_lock(&slab_mutex);
814 list_for_each_entry(s, &slab_root_caches, root_caches_node) {
815 arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
816 lockdep_is_held(&slab_mutex));
817 c = arr->entries[idx];
821 kmemcg_cache_deactivate(c);
822 arr->entries[idx] = NULL;
825 list_for_each_entry(s, &memcg->kmem_caches,
826 memcg_params.kmem_caches_node) {
827 WRITE_ONCE(s->memcg_params.memcg, parent);
828 css_put(&memcg->css);
832 list_splice_init(&memcg->kmem_caches,
833 &parent->kmem_caches);
834 css_get_many(&parent->css, nr_reparented);
836 mutex_unlock(&slab_mutex);
842 static int shutdown_memcg_caches(struct kmem_cache *s)
844 struct memcg_cache_array *arr;
845 struct kmem_cache *c, *c2;
849 BUG_ON(!is_root_cache(s));
852 * First, shutdown active caches, i.e. caches that belong to online
855 arr = rcu_dereference_protected(s->memcg_params.memcg_caches,
856 lockdep_is_held(&slab_mutex));
857 for_each_memcg_cache_index(i) {
861 if (shutdown_cache(c))
863 * The cache still has objects. Move it to a temporary
864 * list so as not to try to destroy it for a second
865 * time while iterating over inactive caches below.
867 list_move(&c->memcg_params.children_node, &busy);
870 * The cache is empty and will be destroyed soon. Clear
871 * the pointer to it in the memcg_caches array so that
872 * it will never be accessed even if the root cache
875 arr->entries[i] = NULL;
879 * Second, shutdown all caches left from memory cgroups that are now
882 list_for_each_entry_safe(c, c2, &s->memcg_params.children,
883 memcg_params.children_node)
886 list_splice(&busy, &s->memcg_params.children);
889 * A cache being destroyed must be empty. In particular, this means
890 * that all per memcg caches attached to it must be empty too.
892 if (!list_empty(&s->memcg_params.children))
897 static void memcg_set_kmem_cache_dying(struct kmem_cache *s)
899 spin_lock_irq(&memcg_kmem_wq_lock);
900 s->memcg_params.dying = true;
901 spin_unlock_irq(&memcg_kmem_wq_lock);
904 static void flush_memcg_workqueue(struct kmem_cache *s)
907 * SLAB and SLUB deactivate the kmem_caches through call_rcu. Make
908 * sure all registered rcu callbacks have been invoked.
913 * SLAB and SLUB create memcg kmem_caches through workqueue and SLUB
914 * deactivates the memcg kmem_caches through workqueue. Make sure all
915 * previous workitems on workqueue are processed.
917 if (likely(memcg_kmem_cache_wq))
918 flush_workqueue(memcg_kmem_cache_wq);
921 * If we're racing with children kmem_cache deactivation, it might
922 * take another rcu grace period to complete their destruction.
923 * At this moment the corresponding percpu_ref_kill() call should be
924 * done, but it might take another rcu grace period to complete
925 * switching to the atomic mode.
926 * Please, note that we check without grabbing the slab_mutex. It's safe
927 * because at this moment the children list can't grow.
929 if (!list_empty(&s->memcg_params.children))
933 static inline int shutdown_memcg_caches(struct kmem_cache *s)
937 #endif /* CONFIG_MEMCG_KMEM */
939 void slab_kmem_cache_release(struct kmem_cache *s)
941 __kmem_cache_release(s);
942 destroy_memcg_params(s);
943 kfree_const(s->name);
944 kmem_cache_free(kmem_cache, s);
947 void kmem_cache_destroy(struct kmem_cache *s)
957 mutex_lock(&slab_mutex);
963 #ifdef CONFIG_MEMCG_KMEM
964 memcg_set_kmem_cache_dying(s);
966 mutex_unlock(&slab_mutex);
971 flush_memcg_workqueue(s);
976 mutex_lock(&slab_mutex);
979 err = shutdown_memcg_caches(s);
981 err = shutdown_cache(s);
984 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
989 mutex_unlock(&slab_mutex);
994 EXPORT_SYMBOL(kmem_cache_destroy);
997 * kmem_cache_shrink - Shrink a cache.
998 * @cachep: The cache to shrink.
1000 * Releases as many slabs as possible for a cache.
1001 * To help debugging, a zero exit status indicates all slabs were released.
1003 * Return: %0 if all slabs were released, non-zero otherwise
1005 int kmem_cache_shrink(struct kmem_cache *cachep)
1011 kasan_cache_shrink(cachep);
1012 ret = __kmem_cache_shrink(cachep);
1017 EXPORT_SYMBOL(kmem_cache_shrink);
1020 * kmem_cache_shrink_all - shrink a cache and all memcg caches for root cache
1021 * @s: The cache pointer
1023 void kmem_cache_shrink_all(struct kmem_cache *s)
1025 struct kmem_cache *c;
1027 if (!IS_ENABLED(CONFIG_MEMCG_KMEM) || !is_root_cache(s)) {
1028 kmem_cache_shrink(s);
1034 kasan_cache_shrink(s);
1035 __kmem_cache_shrink(s);
1038 * We have to take the slab_mutex to protect from the memcg list
1041 mutex_lock(&slab_mutex);
1042 for_each_memcg_cache(c, s) {
1044 * Don't need to shrink deactivated memcg caches.
1046 if (s->flags & SLAB_DEACTIVATED)
1048 kasan_cache_shrink(c);
1049 __kmem_cache_shrink(c);
1051 mutex_unlock(&slab_mutex);
1056 bool slab_is_available(void)
1058 return slab_state >= UP;
1062 /* Create a cache during boot when no slab services are available yet */
1063 void __init create_boot_cache(struct kmem_cache *s, const char *name,
1064 unsigned int size, slab_flags_t flags,
1065 unsigned int useroffset, unsigned int usersize)
1068 unsigned int align = ARCH_KMALLOC_MINALIGN;
1071 s->size = s->object_size = size;
1074 * For power of two sizes, guarantee natural alignment for kmalloc
1075 * caches, regardless of SL*B debugging options.
1077 if (is_power_of_2(size))
1078 align = max(align, size);
1079 s->align = calculate_alignment(flags, align, size);
1081 s->useroffset = useroffset;
1082 s->usersize = usersize;
1084 slab_init_memcg_params(s);
1086 err = __kmem_cache_create(s, flags);
1089 panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
1092 s->refcount = -1; /* Exempt from merging for now */
1095 struct kmem_cache *__init create_kmalloc_cache(const char *name,
1096 unsigned int size, slab_flags_t flags,
1097 unsigned int useroffset, unsigned int usersize)
1099 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
1102 panic("Out of memory when creating slab %s\n", name);
1104 create_boot_cache(s, name, size, flags, useroffset, usersize);
1105 list_add(&s->list, &slab_caches);
1106 memcg_link_cache(s, NULL);
1112 kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
1113 { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
1114 EXPORT_SYMBOL(kmalloc_caches);
1117 * Conversion table for small slabs sizes / 8 to the index in the
1118 * kmalloc array. This is necessary for slabs < 192 since we have non power
1119 * of two cache sizes there. The size of larger slabs can be determined using
1122 static u8 size_index[24] __ro_after_init = {
1149 static inline unsigned int size_index_elem(unsigned int bytes)
1151 return (bytes - 1) / 8;
1155 * Find the kmem_cache structure that serves a given size of
1158 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
1164 return ZERO_SIZE_PTR;
1166 index = size_index[size_index_elem(size)];
1168 if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
1170 index = fls(size - 1);
1173 return kmalloc_caches[kmalloc_type(flags)][index];
1176 #ifdef CONFIG_ZONE_DMA
1177 #define INIT_KMALLOC_INFO(__size, __short_size) \
1179 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
1180 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
1181 .name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \
1185 #define INIT_KMALLOC_INFO(__size, __short_size) \
1187 .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
1188 .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
1194 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
1195 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
1198 const struct kmalloc_info_struct kmalloc_info[] __initconst = {
1199 INIT_KMALLOC_INFO(0, 0),
1200 INIT_KMALLOC_INFO(96, 96),
1201 INIT_KMALLOC_INFO(192, 192),
1202 INIT_KMALLOC_INFO(8, 8),
1203 INIT_KMALLOC_INFO(16, 16),
1204 INIT_KMALLOC_INFO(32, 32),
1205 INIT_KMALLOC_INFO(64, 64),
1206 INIT_KMALLOC_INFO(128, 128),
1207 INIT_KMALLOC_INFO(256, 256),
1208 INIT_KMALLOC_INFO(512, 512),
1209 INIT_KMALLOC_INFO(1024, 1k),
1210 INIT_KMALLOC_INFO(2048, 2k),
1211 INIT_KMALLOC_INFO(4096, 4k),
1212 INIT_KMALLOC_INFO(8192, 8k),
1213 INIT_KMALLOC_INFO(16384, 16k),
1214 INIT_KMALLOC_INFO(32768, 32k),
1215 INIT_KMALLOC_INFO(65536, 64k),
1216 INIT_KMALLOC_INFO(131072, 128k),
1217 INIT_KMALLOC_INFO(262144, 256k),
1218 INIT_KMALLOC_INFO(524288, 512k),
1219 INIT_KMALLOC_INFO(1048576, 1M),
1220 INIT_KMALLOC_INFO(2097152, 2M),
1221 INIT_KMALLOC_INFO(4194304, 4M),
1222 INIT_KMALLOC_INFO(8388608, 8M),
1223 INIT_KMALLOC_INFO(16777216, 16M),
1224 INIT_KMALLOC_INFO(33554432, 32M),
1225 INIT_KMALLOC_INFO(67108864, 64M)
1229 * Patch up the size_index table if we have strange large alignment
1230 * requirements for the kmalloc array. This is only the case for
1231 * MIPS it seems. The standard arches will not generate any code here.
1233 * Largest permitted alignment is 256 bytes due to the way we
1234 * handle the index determination for the smaller caches.
1236 * Make sure that nothing crazy happens if someone starts tinkering
1237 * around with ARCH_KMALLOC_MINALIGN
1239 void __init setup_kmalloc_cache_index_table(void)
1243 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
1244 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
1246 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
1247 unsigned int elem = size_index_elem(i);
1249 if (elem >= ARRAY_SIZE(size_index))
1251 size_index[elem] = KMALLOC_SHIFT_LOW;
1254 if (KMALLOC_MIN_SIZE >= 64) {
1256 * The 96 byte size cache is not used if the alignment
1259 for (i = 64 + 8; i <= 96; i += 8)
1260 size_index[size_index_elem(i)] = 7;
1264 if (KMALLOC_MIN_SIZE >= 128) {
1266 * The 192 byte sized cache is not used if the alignment
1267 * is 128 byte. Redirect kmalloc to use the 256 byte cache
1270 for (i = 128 + 8; i <= 192; i += 8)
1271 size_index[size_index_elem(i)] = 8;
1276 new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
1278 if (type == KMALLOC_RECLAIM)
1279 flags |= SLAB_RECLAIM_ACCOUNT;
1281 kmalloc_caches[type][idx] = create_kmalloc_cache(
1282 kmalloc_info[idx].name[type],
1283 kmalloc_info[idx].size, flags, 0,
1284 kmalloc_info[idx].size);
1288 * Create the kmalloc array. Some of the regular kmalloc arrays
1289 * may already have been created because they were needed to
1290 * enable allocations for slab creation.
1292 void __init create_kmalloc_caches(slab_flags_t flags)
1295 enum kmalloc_cache_type type;
1297 for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
1298 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
1299 if (!kmalloc_caches[type][i])
1300 new_kmalloc_cache(i, type, flags);
1303 * Caches that are not of the two-to-the-power-of size.
1304 * These have to be created immediately after the
1305 * earlier power of two caches
1307 if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
1308 !kmalloc_caches[type][1])
1309 new_kmalloc_cache(1, type, flags);
1310 if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
1311 !kmalloc_caches[type][2])
1312 new_kmalloc_cache(2, type, flags);
1316 /* Kmalloc array is now usable */
1319 #ifdef CONFIG_ZONE_DMA
1320 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
1321 struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
1324 kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
1325 kmalloc_info[i].name[KMALLOC_DMA],
1326 kmalloc_info[i].size,
1327 SLAB_CACHE_DMA | flags, 0,
1328 kmalloc_info[i].size);
1333 #endif /* !CONFIG_SLOB */
1336 * To avoid unnecessary overhead, we pass through large allocation requests
1337 * directly to the page allocator. We use __GFP_COMP, because we will need to
1338 * know the allocation order to free the pages properly in kfree.
1340 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
1345 flags |= __GFP_COMP;
1346 page = alloc_pages(flags, order);
1348 ret = page_address(page);
1349 mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
1352 ret = kasan_kmalloc_large(ret, size, flags);
1353 /* As ret might get tagged, call kmemleak hook after KASAN. */
1354 kmemleak_alloc(ret, size, 1, flags);
1357 EXPORT_SYMBOL(kmalloc_order);
1359 #ifdef CONFIG_TRACING
1360 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
1362 void *ret = kmalloc_order(size, flags, order);
1363 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
1366 EXPORT_SYMBOL(kmalloc_order_trace);
1369 #ifdef CONFIG_SLAB_FREELIST_RANDOM
1370 /* Randomize a generic freelist */
1371 static void freelist_randomize(struct rnd_state *state, unsigned int *list,
1377 for (i = 0; i < count; i++)
1380 /* Fisher-Yates shuffle */
1381 for (i = count - 1; i > 0; i--) {
1382 rand = prandom_u32_state(state);
1384 swap(list[i], list[rand]);
1388 /* Create a random sequence per cache */
1389 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
1392 struct rnd_state state;
1394 if (count < 2 || cachep->random_seq)
1397 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
1398 if (!cachep->random_seq)
1401 /* Get best entropy at this stage of boot */
1402 prandom_seed_state(&state, get_random_long());
1404 freelist_randomize(&state, cachep->random_seq, count);
1408 /* Destroy the per-cache random freelist sequence */
1409 void cache_random_seq_destroy(struct kmem_cache *cachep)
1411 kfree(cachep->random_seq);
1412 cachep->random_seq = NULL;
1414 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
1416 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
1418 #define SLABINFO_RIGHTS (0600)
1420 #define SLABINFO_RIGHTS (0400)
1423 static void print_slabinfo_header(struct seq_file *m)
1426 * Output format version, so at least we can change it
1427 * without _too_ many complaints.
1429 #ifdef CONFIG_DEBUG_SLAB
1430 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
1432 seq_puts(m, "slabinfo - version: 2.1\n");
1434 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
1435 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
1436 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
1437 #ifdef CONFIG_DEBUG_SLAB
1438 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
1439 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
1444 void *slab_start(struct seq_file *m, loff_t *pos)
1446 mutex_lock(&slab_mutex);
1447 return seq_list_start(&slab_root_caches, *pos);
1450 void *slab_next(struct seq_file *m, void *p, loff_t *pos)
1452 return seq_list_next(p, &slab_root_caches, pos);
1455 void slab_stop(struct seq_file *m, void *p)
1457 mutex_unlock(&slab_mutex);
1461 memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info)
1463 struct kmem_cache *c;
1464 struct slabinfo sinfo;
1466 if (!is_root_cache(s))
1469 for_each_memcg_cache(c, s) {
1470 memset(&sinfo, 0, sizeof(sinfo));
1471 get_slabinfo(c, &sinfo);
1473 info->active_slabs += sinfo.active_slabs;
1474 info->num_slabs += sinfo.num_slabs;
1475 info->shared_avail += sinfo.shared_avail;
1476 info->active_objs += sinfo.active_objs;
1477 info->num_objs += sinfo.num_objs;
1481 static void cache_show(struct kmem_cache *s, struct seq_file *m)
1483 struct slabinfo sinfo;
1485 memset(&sinfo, 0, sizeof(sinfo));
1486 get_slabinfo(s, &sinfo);
1488 memcg_accumulate_slabinfo(s, &sinfo);
1490 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
1491 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size,
1492 sinfo.objects_per_slab, (1 << sinfo.cache_order));
1494 seq_printf(m, " : tunables %4u %4u %4u",
1495 sinfo.limit, sinfo.batchcount, sinfo.shared);
1496 seq_printf(m, " : slabdata %6lu %6lu %6lu",
1497 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
1498 slabinfo_show_stats(m, s);
1502 static int slab_show(struct seq_file *m, void *p)
1504 struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node);
1506 if (p == slab_root_caches.next)
1507 print_slabinfo_header(m);
1512 void dump_unreclaimable_slab(void)
1514 struct kmem_cache *s, *s2;
1515 struct slabinfo sinfo;
1518 * Here acquiring slab_mutex is risky since we don't prefer to get
1519 * sleep in oom path. But, without mutex hold, it may introduce a
1521 * Use mutex_trylock to protect the list traverse, dump nothing
1522 * without acquiring the mutex.
1524 if (!mutex_trylock(&slab_mutex)) {
1525 pr_warn("excessive unreclaimable slab but cannot dump stats\n");
1529 pr_info("Unreclaimable slab info:\n");
1530 pr_info("Name Used Total\n");
1532 list_for_each_entry_safe(s, s2, &slab_caches, list) {
1533 if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT))
1536 get_slabinfo(s, &sinfo);
1538 if (sinfo.num_objs > 0)
1539 pr_info("%-17s %10luKB %10luKB\n", cache_name(s),
1540 (sinfo.active_objs * s->size) / 1024,
1541 (sinfo.num_objs * s->size) / 1024);
1543 mutex_unlock(&slab_mutex);
1546 #if defined(CONFIG_MEMCG_KMEM)
1547 void *memcg_slab_start(struct seq_file *m, loff_t *pos)
1549 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
1551 mutex_lock(&slab_mutex);
1552 return seq_list_start(&memcg->kmem_caches, *pos);
1555 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos)
1557 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
1559 return seq_list_next(p, &memcg->kmem_caches, pos);
1562 void memcg_slab_stop(struct seq_file *m, void *p)
1564 mutex_unlock(&slab_mutex);
1567 int memcg_slab_show(struct seq_file *m, void *p)
1569 struct kmem_cache *s = list_entry(p, struct kmem_cache,
1570 memcg_params.kmem_caches_node);
1571 struct mem_cgroup *memcg = mem_cgroup_from_seq(m);
1573 if (p == memcg->kmem_caches.next)
1574 print_slabinfo_header(m);
1581 * slabinfo_op - iterator that generates /proc/slabinfo
1590 * num-pages-per-slab
1591 * + further values on SMP and with statistics enabled
1593 static const struct seq_operations slabinfo_op = {
1594 .start = slab_start,
1600 static int slabinfo_open(struct inode *inode, struct file *file)
1602 return seq_open(file, &slabinfo_op);
1605 static const struct proc_ops slabinfo_proc_ops = {
1606 .proc_flags = PROC_ENTRY_PERMANENT,
1607 .proc_open = slabinfo_open,
1608 .proc_read = seq_read,
1609 .proc_write = slabinfo_write,
1610 .proc_lseek = seq_lseek,
1611 .proc_release = seq_release,
1614 static int __init slab_proc_init(void)
1616 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
1619 module_init(slab_proc_init);
1621 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_MEMCG_KMEM)
1623 * Display information about kmem caches that have child memcg caches.
1625 static int memcg_slabinfo_show(struct seq_file *m, void *unused)
1627 struct kmem_cache *s, *c;
1628 struct slabinfo sinfo;
1630 mutex_lock(&slab_mutex);
1631 seq_puts(m, "# <name> <css_id[:dead|deact]> <active_objs> <num_objs>");
1632 seq_puts(m, " <active_slabs> <num_slabs>\n");
1633 list_for_each_entry(s, &slab_root_caches, root_caches_node) {
1635 * Skip kmem caches that don't have any memcg children.
1637 if (list_empty(&s->memcg_params.children))
1640 memset(&sinfo, 0, sizeof(sinfo));
1641 get_slabinfo(s, &sinfo);
1642 seq_printf(m, "%-17s root %6lu %6lu %6lu %6lu\n",
1643 cache_name(s), sinfo.active_objs, sinfo.num_objs,
1644 sinfo.active_slabs, sinfo.num_slabs);
1646 for_each_memcg_cache(c, s) {
1647 struct cgroup_subsys_state *css;
1650 css = &c->memcg_params.memcg->css;
1651 if (!(css->flags & CSS_ONLINE))
1653 else if (c->flags & SLAB_DEACTIVATED)
1656 memset(&sinfo, 0, sizeof(sinfo));
1657 get_slabinfo(c, &sinfo);
1658 seq_printf(m, "%-17s %4d%-6s %6lu %6lu %6lu %6lu\n",
1659 cache_name(c), css->id, status,
1660 sinfo.active_objs, sinfo.num_objs,
1661 sinfo.active_slabs, sinfo.num_slabs);
1664 mutex_unlock(&slab_mutex);
1667 DEFINE_SHOW_ATTRIBUTE(memcg_slabinfo);
1669 static int __init memcg_slabinfo_init(void)
1671 debugfs_create_file("memcg_slabinfo", S_IFREG | S_IRUGO,
1672 NULL, NULL, &memcg_slabinfo_fops);
1676 late_initcall(memcg_slabinfo_init);
1677 #endif /* CONFIG_DEBUG_FS && CONFIG_MEMCG_KMEM */
1678 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
1680 static __always_inline void *__do_krealloc(const void *p, size_t new_size,
1689 if (ks >= new_size) {
1690 p = kasan_krealloc((void *)p, new_size, flags);
1694 ret = kmalloc_track_caller(new_size, flags);
1702 * krealloc - reallocate memory. The contents will remain unchanged.
1703 * @p: object to reallocate memory for.
1704 * @new_size: how many bytes of memory are required.
1705 * @flags: the type of memory to allocate.
1707 * The contents of the object pointed to are preserved up to the
1708 * lesser of the new and old sizes. If @p is %NULL, krealloc()
1709 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
1710 * %NULL pointer, the object pointed to is freed.
1712 * Return: pointer to the allocated memory or %NULL in case of error
1714 void *krealloc(const void *p, size_t new_size, gfp_t flags)
1718 if (unlikely(!new_size)) {
1720 return ZERO_SIZE_PTR;
1723 ret = __do_krealloc(p, new_size, flags);
1724 if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
1729 EXPORT_SYMBOL(krealloc);
1732 * kzfree - like kfree but zero memory
1733 * @p: object to free memory of
1735 * The memory of the object @p points to is zeroed before freed.
1736 * If @p is %NULL, kzfree() does nothing.
1738 * Note: this function zeroes the whole allocated buffer which can be a good
1739 * deal bigger than the requested buffer size passed to kmalloc(). So be
1740 * careful when using this function in performance sensitive code.
1742 void kzfree(const void *p)
1745 void *mem = (void *)p;
1747 if (unlikely(ZERO_OR_NULL_PTR(mem)))
1750 memzero_explicit(mem, ks);
1753 EXPORT_SYMBOL(kzfree);
1756 * ksize - get the actual amount of memory allocated for a given object
1757 * @objp: Pointer to the object
1759 * kmalloc may internally round up allocations and return more memory
1760 * than requested. ksize() can be used to determine the actual amount of
1761 * memory allocated. The caller may use this additional memory, even though
1762 * a smaller amount of memory was initially specified with the kmalloc call.
1763 * The caller must guarantee that objp points to a valid object previously
1764 * allocated with either kmalloc() or kmem_cache_alloc(). The object
1765 * must not be freed during the duration of the call.
1767 * Return: size of the actual memory used by @objp in bytes
1769 size_t ksize(const void *objp)
1773 if (WARN_ON_ONCE(!objp))
1776 * We need to check that the pointed to object is valid, and only then
1777 * unpoison the shadow memory below. We use __kasan_check_read(), to
1778 * generate a more useful report at the time ksize() is called (rather
1779 * than later where behaviour is undefined due to potential
1780 * use-after-free or double-free).
1782 * If the pointed to memory is invalid we return 0, to avoid users of
1783 * ksize() writing to and potentially corrupting the memory region.
1785 * We want to perform the check before __ksize(), to avoid potentially
1786 * crashing in __ksize() due to accessing invalid metadata.
1788 if (unlikely(objp == ZERO_SIZE_PTR) || !__kasan_check_read(objp, 1))
1791 size = __ksize(objp);
1793 * We assume that ksize callers could use whole allocated area,
1794 * so we need to unpoison this area.
1796 kasan_unpoison_shadow(objp, size);
1799 EXPORT_SYMBOL(ksize);
1801 /* Tracepoints definitions. */
1802 EXPORT_TRACEPOINT_SYMBOL(kmalloc);
1803 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
1804 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
1805 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
1806 EXPORT_TRACEPOINT_SYMBOL(kfree);
1807 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
1809 int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
1811 if (__should_failslab(s, gfpflags))
1815 ALLOW_ERROR_INJECTION(should_failslab, ERRNO);