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- // SPDX-License-Identifier: GPL-2.0
- /*
- * Slab allocator functions that are independent of the allocator strategy
- *
- * (C) 2012 Christoph Lameter <cl@linux.com>
- */
- #include <linux/slab.h>
- #include <linux/mm.h>
- #include <linux/poison.h>
- #include <linux/interrupt.h>
- #include <linux/memory.h>
- #include <linux/cache.h>
- #include <linux/compiler.h>
- #include <linux/kfence.h>
- #include <linux/module.h>
- #include <linux/cpu.h>
- #include <linux/uaccess.h>
- #include <linux/seq_file.h>
- #include <linux/proc_fs.h>
- #include <linux/debugfs.h>
- #include <linux/kasan.h>
- #include <asm/cacheflush.h>
- #include <asm/tlbflush.h>
- #include <asm/page.h>
- #include <linux/memcontrol.h>
- #define CREATE_TRACE_POINTS
- #include <trace/events/kmem.h>
- #undef CREATE_TRACE_POINTS
- #include <trace/hooks/mm.h>
- #include "internal.h"
- #include "slab.h"
- enum slab_state slab_state;
- LIST_HEAD(slab_caches);
- DEFINE_MUTEX(slab_mutex);
- struct kmem_cache *kmem_cache;
- #ifdef CONFIG_HARDENED_USERCOPY
- bool usercopy_fallback __ro_after_init =
- IS_ENABLED(CONFIG_HARDENED_USERCOPY_FALLBACK);
- module_param(usercopy_fallback, bool, 0400);
- MODULE_PARM_DESC(usercopy_fallback,
- "WARN instead of reject usercopy whitelist violations");
- #endif
- static LIST_HEAD(slab_caches_to_rcu_destroy);
- static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
- static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
- slab_caches_to_rcu_destroy_workfn);
- /*
- * Set of flags that will prevent slab merging
- */
- #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
- SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
- SLAB_FAILSLAB | kasan_never_merge())
- #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
- SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
- /*
- * Merge control. If this is set then no merging of slab caches will occur.
- */
- static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
- static int __init setup_slab_nomerge(char *str)
- {
- slab_nomerge = true;
- return 1;
- }
- #ifdef CONFIG_SLUB
- __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
- #endif
- __setup("slab_nomerge", setup_slab_nomerge);
- /*
- * Determine the size of a slab object
- */
- unsigned int kmem_cache_size(struct kmem_cache *s)
- {
- return s->object_size;
- }
- EXPORT_SYMBOL(kmem_cache_size);
- #ifdef CONFIG_DEBUG_VM
- static int kmem_cache_sanity_check(const char *name, unsigned int size)
- {
- if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) {
- pr_err("kmem_cache_create(%s) integrity check failed\n", name);
- return -EINVAL;
- }
- WARN_ON(strchr(name, ' ')); /* It confuses parsers */
- return 0;
- }
- #else
- static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
- {
- return 0;
- }
- #endif
- void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p)
- {
- size_t i;
- for (i = 0; i < nr; i++) {
- if (s)
- kmem_cache_free(s, p[i]);
- else
- kfree(p[i]);
- }
- }
- int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
- void **p)
- {
- size_t i;
- for (i = 0; i < nr; i++) {
- void *x = p[i] = kmem_cache_alloc(s, flags);
- if (!x) {
- __kmem_cache_free_bulk(s, i, p);
- return 0;
- }
- }
- return i;
- }
- /*
- * Figure out what the alignment of the objects will be given a set of
- * flags, a user specified alignment and the size of the objects.
- */
- static unsigned int calculate_alignment(slab_flags_t flags,
- unsigned int align, unsigned int size)
- {
- /*
- * If the user wants hardware cache aligned objects then follow that
- * suggestion if the object is sufficiently large.
- *
- * The hardware cache alignment cannot override the specified
- * alignment though. If that is greater then use it.
- */
- if (flags & SLAB_HWCACHE_ALIGN) {
- unsigned int ralign;
- ralign = cache_line_size();
- while (size <= ralign / 2)
- ralign /= 2;
- align = max(align, ralign);
- }
- if (align < ARCH_SLAB_MINALIGN)
- align = ARCH_SLAB_MINALIGN;
- return ALIGN(align, sizeof(void *));
- }
- /*
- * Find a mergeable slab cache
- */
- int slab_unmergeable(struct kmem_cache *s)
- {
- if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
- return 1;
- if (s->ctor)
- return 1;
- if (s->usersize)
- return 1;
- /*
- * We may have set a slab to be unmergeable during bootstrap.
- */
- if (s->refcount < 0)
- return 1;
- return 0;
- }
- struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
- slab_flags_t flags, const char *name, void (*ctor)(void *))
- {
- struct kmem_cache *s;
- if (slab_nomerge)
- return NULL;
- if (ctor)
- return NULL;
- size = ALIGN(size, sizeof(void *));
- align = calculate_alignment(flags, align, size);
- size = ALIGN(size, align);
- flags = kmem_cache_flags(size, flags, name);
- if (flags & SLAB_NEVER_MERGE)
- return NULL;
- list_for_each_entry_reverse(s, &slab_caches, list) {
- if (slab_unmergeable(s))
- continue;
- if (size > s->size)
- continue;
- if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
- continue;
- /*
- * Check if alignment is compatible.
- * Courtesy of Adrian Drzewiecki
- */
- if ((s->size & ~(align - 1)) != s->size)
- continue;
- if (s->size - size >= sizeof(void *))
- continue;
- if (IS_ENABLED(CONFIG_SLAB) && align &&
- (align > s->align || s->align % align))
- continue;
- return s;
- }
- return NULL;
- }
- static struct kmem_cache *create_cache(const char *name,
- unsigned int object_size, unsigned int align,
- slab_flags_t flags, unsigned int useroffset,
- unsigned int usersize, void (*ctor)(void *),
- struct kmem_cache *root_cache)
- {
- struct kmem_cache *s;
- int err;
- if (WARN_ON(useroffset + usersize > object_size))
- useroffset = usersize = 0;
- err = -ENOMEM;
- s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
- if (!s)
- goto out;
- s->name = name;
- s->size = s->object_size = object_size;
- s->align = align;
- s->ctor = ctor;
- s->useroffset = useroffset;
- s->usersize = usersize;
- err = __kmem_cache_create(s, flags);
- if (err)
- goto out_free_cache;
- s->refcount = 1;
- list_add(&s->list, &slab_caches);
- out:
- if (err)
- return ERR_PTR(err);
- return s;
- out_free_cache:
- kmem_cache_free(kmem_cache, s);
- goto out;
- }
- /**
- * kmem_cache_create_usercopy - Create a cache with a region suitable
- * for copying to userspace
- * @name: A string which is used in /proc/slabinfo to identify this cache.
- * @size: The size of objects to be created in this cache.
- * @align: The required alignment for the objects.
- * @flags: SLAB flags
- * @useroffset: Usercopy region offset
- * @usersize: Usercopy region size
- * @ctor: A constructor for the objects.
- *
- * Cannot be called within a interrupt, but can be interrupted.
- * The @ctor is run when new pages are allocated by the cache.
- *
- * The flags are
- *
- * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
- * to catch references to uninitialised memory.
- *
- * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
- * for buffer overruns.
- *
- * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
- * cacheline. This can be beneficial if you're counting cycles as closely
- * as davem.
- *
- * Return: a pointer to the cache on success, NULL on failure.
- */
- struct kmem_cache *
- kmem_cache_create_usercopy(const char *name,
- unsigned int size, unsigned int align,
- slab_flags_t flags,
- unsigned int useroffset, unsigned int usersize,
- void (*ctor)(void *))
- {
- struct kmem_cache *s = NULL;
- const char *cache_name;
- int err;
- get_online_cpus();
- get_online_mems();
- #ifdef CONFIG_SLUB_DEBUG
- /*
- * If no slub_debug was enabled globally, the static key is not yet
- * enabled by setup_slub_debug(). Enable it if the cache is being
- * created with any of the debugging flags passed explicitly.
- */
- if (flags & SLAB_DEBUG_FLAGS)
- static_branch_enable(&slub_debug_enabled);
- #endif
- mutex_lock(&slab_mutex);
- err = kmem_cache_sanity_check(name, size);
- if (err) {
- goto out_unlock;
- }
- /* Refuse requests with allocator specific flags */
- if (flags & ~SLAB_FLAGS_PERMITTED) {
- err = -EINVAL;
- goto out_unlock;
- }
- /*
- * Some allocators will constraint the set of valid flags to a subset
- * of all flags. We expect them to define CACHE_CREATE_MASK in this
- * case, and we'll just provide them with a sanitized version of the
- * passed flags.
- */
- flags &= CACHE_CREATE_MASK;
- /* Fail closed on bad usersize of useroffset values. */
- if (WARN_ON(!usersize && useroffset) ||
- WARN_ON(size < usersize || size - usersize < useroffset))
- usersize = useroffset = 0;
- if (!usersize)
- s = __kmem_cache_alias(name, size, align, flags, ctor);
- if (s)
- goto out_unlock;
- cache_name = kstrdup_const(name, GFP_KERNEL);
- if (!cache_name) {
- err = -ENOMEM;
- goto out_unlock;
- }
- s = create_cache(cache_name, size,
- calculate_alignment(flags, align, size),
- flags, useroffset, usersize, ctor, NULL);
- if (IS_ERR(s)) {
- err = PTR_ERR(s);
- kfree_const(cache_name);
- }
- out_unlock:
- mutex_unlock(&slab_mutex);
- put_online_mems();
- put_online_cpus();
- if (err) {
- if (flags & SLAB_PANIC)
- panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n",
- name, err);
- else {
- pr_warn("kmem_cache_create(%s) failed with error %d\n",
- name, err);
- dump_stack();
- }
- return NULL;
- }
- return s;
- }
- EXPORT_SYMBOL(kmem_cache_create_usercopy);
- /**
- * kmem_cache_create - Create a cache.
- * @name: A string which is used in /proc/slabinfo to identify this cache.
- * @size: The size of objects to be created in this cache.
- * @align: The required alignment for the objects.
- * @flags: SLAB flags
- * @ctor: A constructor for the objects.
- *
- * Cannot be called within a interrupt, but can be interrupted.
- * The @ctor is run when new pages are allocated by the cache.
- *
- * The flags are
- *
- * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
- * to catch references to uninitialised memory.
- *
- * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
- * for buffer overruns.
- *
- * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
- * cacheline. This can be beneficial if you're counting cycles as closely
- * as davem.
- *
- * Return: a pointer to the cache on success, NULL on failure.
- */
- struct kmem_cache *
- kmem_cache_create(const char *name, unsigned int size, unsigned int align,
- slab_flags_t flags, void (*ctor)(void *))
- {
- return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
- ctor);
- }
- EXPORT_SYMBOL(kmem_cache_create);
- static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
- {
- LIST_HEAD(to_destroy);
- struct kmem_cache *s, *s2;
- /*
- * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
- * @slab_caches_to_rcu_destroy list. The slab pages are freed
- * through RCU and the associated kmem_cache are dereferenced
- * while freeing the pages, so the kmem_caches should be freed only
- * after the pending RCU operations are finished. As rcu_barrier()
- * is a pretty slow operation, we batch all pending destructions
- * asynchronously.
- */
- mutex_lock(&slab_mutex);
- list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
- mutex_unlock(&slab_mutex);
- if (list_empty(&to_destroy))
- return;
- rcu_barrier();
- list_for_each_entry_safe(s, s2, &to_destroy, list) {
- debugfs_slab_release(s);
- kfence_shutdown_cache(s);
- #ifdef SLAB_SUPPORTS_SYSFS
- sysfs_slab_release(s);
- #else
- slab_kmem_cache_release(s);
- #endif
- }
- }
- static int shutdown_cache(struct kmem_cache *s)
- {
- /* free asan quarantined objects */
- kasan_cache_shutdown(s);
- if (__kmem_cache_shutdown(s) != 0)
- return -EBUSY;
- list_del(&s->list);
- if (s->flags & SLAB_TYPESAFE_BY_RCU) {
- #ifdef SLAB_SUPPORTS_SYSFS
- sysfs_slab_unlink(s);
- #endif
- list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
- schedule_work(&slab_caches_to_rcu_destroy_work);
- } else {
- kfence_shutdown_cache(s);
- debugfs_slab_release(s);
- #ifdef SLAB_SUPPORTS_SYSFS
- sysfs_slab_unlink(s);
- sysfs_slab_release(s);
- #else
- slab_kmem_cache_release(s);
- #endif
- }
- return 0;
- }
- void slab_kmem_cache_release(struct kmem_cache *s)
- {
- __kmem_cache_release(s);
- kfree_const(s->name);
- kmem_cache_free(kmem_cache, s);
- }
- void kmem_cache_destroy(struct kmem_cache *s)
- {
- int err;
- if (unlikely(!s))
- return;
- get_online_cpus();
- get_online_mems();
- mutex_lock(&slab_mutex);
- s->refcount--;
- if (s->refcount)
- goto out_unlock;
- err = shutdown_cache(s);
- if (err) {
- pr_err("kmem_cache_destroy %s: Slab cache still has objects\n",
- s->name);
- dump_stack();
- }
- out_unlock:
- mutex_unlock(&slab_mutex);
- put_online_mems();
- put_online_cpus();
- }
- EXPORT_SYMBOL(kmem_cache_destroy);
- /**
- * kmem_cache_shrink - Shrink a cache.
- * @cachep: The cache to shrink.
- *
- * Releases as many slabs as possible for a cache.
- * To help debugging, a zero exit status indicates all slabs were released.
- *
- * Return: %0 if all slabs were released, non-zero otherwise
- */
- int kmem_cache_shrink(struct kmem_cache *cachep)
- {
- int ret;
- get_online_cpus();
- get_online_mems();
- kasan_cache_shrink(cachep);
- ret = __kmem_cache_shrink(cachep);
- put_online_mems();
- put_online_cpus();
- return ret;
- }
- EXPORT_SYMBOL(kmem_cache_shrink);
- bool slab_is_available(void)
- {
- return slab_state >= UP;
- }
- #ifndef CONFIG_SLOB
- /* Create a cache during boot when no slab services are available yet */
- void __init create_boot_cache(struct kmem_cache *s, const char *name,
- unsigned int size, slab_flags_t flags,
- unsigned int useroffset, unsigned int usersize)
- {
- int err;
- unsigned int align = ARCH_KMALLOC_MINALIGN;
- s->name = name;
- s->size = s->object_size = size;
- /*
- * For power of two sizes, guarantee natural alignment for kmalloc
- * caches, regardless of SL*B debugging options.
- */
- if (is_power_of_2(size))
- align = max(align, size);
- s->align = calculate_alignment(flags, align, size);
- s->useroffset = useroffset;
- s->usersize = usersize;
- err = __kmem_cache_create(s, flags);
- if (err)
- panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",
- name, size, err);
- s->refcount = -1; /* Exempt from merging for now */
- }
- struct kmem_cache *__init create_kmalloc_cache(const char *name,
- unsigned int size, slab_flags_t flags,
- unsigned int useroffset, unsigned int usersize)
- {
- struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
- if (!s)
- panic("Out of memory when creating slab %s\n", name);
- create_boot_cache(s, name, size, flags, useroffset, usersize);
- kasan_cache_create_kmalloc(s);
- list_add(&s->list, &slab_caches);
- s->refcount = 1;
- return s;
- }
- struct kmem_cache *
- kmalloc_caches[NR_KMALLOC_TYPES][KMALLOC_SHIFT_HIGH + 1] __ro_after_init =
- { /* initialization for https://bugs.llvm.org/show_bug.cgi?id=42570 */ };
- EXPORT_SYMBOL(kmalloc_caches);
- /*
- * Conversion table for small slabs sizes / 8 to the index in the
- * kmalloc array. This is necessary for slabs < 192 since we have non power
- * of two cache sizes there. The size of larger slabs can be determined using
- * fls.
- */
- static u8 size_index[24] __ro_after_init = {
- 3, /* 8 */
- 4, /* 16 */
- 5, /* 24 */
- 5, /* 32 */
- 6, /* 40 */
- 6, /* 48 */
- 6, /* 56 */
- 6, /* 64 */
- 1, /* 72 */
- 1, /* 80 */
- 1, /* 88 */
- 1, /* 96 */
- 7, /* 104 */
- 7, /* 112 */
- 7, /* 120 */
- 7, /* 128 */
- 2, /* 136 */
- 2, /* 144 */
- 2, /* 152 */
- 2, /* 160 */
- 2, /* 168 */
- 2, /* 176 */
- 2, /* 184 */
- 2 /* 192 */
- };
- static inline unsigned int size_index_elem(unsigned int bytes)
- {
- return (bytes - 1) / 8;
- }
- /*
- * Find the kmem_cache structure that serves a given size of
- * allocation
- */
- struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags)
- {
- unsigned int index;
- struct kmem_cache *s = NULL;
- if (size <= 192) {
- if (!size)
- return ZERO_SIZE_PTR;
- index = size_index[size_index_elem(size)];
- } else {
- if (WARN_ON_ONCE(size > KMALLOC_MAX_CACHE_SIZE))
- return NULL;
- index = fls(size - 1);
- }
- trace_android_vh_kmalloc_slab(index, flags, &s);
- if (s)
- return s;
- return kmalloc_caches[kmalloc_type(flags)][index];
- }
- #ifdef CONFIG_ZONE_DMA
- #define INIT_KMALLOC_INFO(__size, __short_size) \
- { \
- .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
- .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
- .name[KMALLOC_DMA] = "dma-kmalloc-" #__short_size, \
- .size = __size, \
- }
- #else
- #define INIT_KMALLOC_INFO(__size, __short_size) \
- { \
- .name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
- .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
- .size = __size, \
- }
- #endif
- /*
- * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time.
- * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is
- * kmalloc-67108864.
- */
- const struct kmalloc_info_struct kmalloc_info[] __initconst = {
- INIT_KMALLOC_INFO(0, 0),
- INIT_KMALLOC_INFO(96, 96),
- INIT_KMALLOC_INFO(192, 192),
- INIT_KMALLOC_INFO(8, 8),
- INIT_KMALLOC_INFO(16, 16),
- INIT_KMALLOC_INFO(32, 32),
- INIT_KMALLOC_INFO(64, 64),
- INIT_KMALLOC_INFO(128, 128),
- INIT_KMALLOC_INFO(256, 256),
- INIT_KMALLOC_INFO(512, 512),
- INIT_KMALLOC_INFO(1024, 1k),
- INIT_KMALLOC_INFO(2048, 2k),
- INIT_KMALLOC_INFO(4096, 4k),
- INIT_KMALLOC_INFO(8192, 8k),
- INIT_KMALLOC_INFO(16384, 16k),
- INIT_KMALLOC_INFO(32768, 32k),
- INIT_KMALLOC_INFO(65536, 64k),
- INIT_KMALLOC_INFO(131072, 128k),
- INIT_KMALLOC_INFO(262144, 256k),
- INIT_KMALLOC_INFO(524288, 512k),
- INIT_KMALLOC_INFO(1048576, 1M),
- INIT_KMALLOC_INFO(2097152, 2M),
- INIT_KMALLOC_INFO(4194304, 4M),
- INIT_KMALLOC_INFO(8388608, 8M),
- INIT_KMALLOC_INFO(16777216, 16M),
- INIT_KMALLOC_INFO(33554432, 32M),
- INIT_KMALLOC_INFO(67108864, 64M)
- };
- /*
- * Patch up the size_index table if we have strange large alignment
- * requirements for the kmalloc array. This is only the case for
- * MIPS it seems. The standard arches will not generate any code here.
- *
- * Largest permitted alignment is 256 bytes due to the way we
- * handle the index determination for the smaller caches.
- *
- * Make sure that nothing crazy happens if someone starts tinkering
- * around with ARCH_KMALLOC_MINALIGN
- */
- void __init setup_kmalloc_cache_index_table(void)
- {
- unsigned int i;
- BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
- (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
- for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
- unsigned int elem = size_index_elem(i);
- if (elem >= ARRAY_SIZE(size_index))
- break;
- size_index[elem] = KMALLOC_SHIFT_LOW;
- }
- if (KMALLOC_MIN_SIZE >= 64) {
- /*
- * The 96 byte size cache is not used if the alignment
- * is 64 byte.
- */
- for (i = 64 + 8; i <= 96; i += 8)
- size_index[size_index_elem(i)] = 7;
- }
- if (KMALLOC_MIN_SIZE >= 128) {
- /*
- * The 192 byte sized cache is not used if the alignment
- * is 128 byte. Redirect kmalloc to use the 256 byte cache
- * instead.
- */
- for (i = 128 + 8; i <= 192; i += 8)
- size_index[size_index_elem(i)] = 8;
- }
- }
- static void __init
- new_kmalloc_cache(int idx, enum kmalloc_cache_type type, slab_flags_t flags)
- {
- if (type == KMALLOC_RECLAIM)
- flags |= SLAB_RECLAIM_ACCOUNT;
- kmalloc_caches[type][idx] = create_kmalloc_cache(
- kmalloc_info[idx].name[type],
- kmalloc_info[idx].size, flags, 0,
- kmalloc_info[idx].size);
- }
- /*
- * Create the kmalloc array. Some of the regular kmalloc arrays
- * may already have been created because they were needed to
- * enable allocations for slab creation.
- */
- void __init create_kmalloc_caches(slab_flags_t flags)
- {
- int i;
- enum kmalloc_cache_type type;
- for (type = KMALLOC_NORMAL; type <= KMALLOC_RECLAIM; type++) {
- for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
- if (!kmalloc_caches[type][i])
- new_kmalloc_cache(i, type, flags);
- /*
- * Caches that are not of the two-to-the-power-of size.
- * These have to be created immediately after the
- * earlier power of two caches
- */
- if (KMALLOC_MIN_SIZE <= 32 && i == 6 &&
- !kmalloc_caches[type][1])
- new_kmalloc_cache(1, type, flags);
- if (KMALLOC_MIN_SIZE <= 64 && i == 7 &&
- !kmalloc_caches[type][2])
- new_kmalloc_cache(2, type, flags);
- }
- }
- /* Kmalloc array is now usable */
- slab_state = UP;
- #ifdef CONFIG_ZONE_DMA
- for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) {
- struct kmem_cache *s = kmalloc_caches[KMALLOC_NORMAL][i];
- if (s) {
- kmalloc_caches[KMALLOC_DMA][i] = create_kmalloc_cache(
- kmalloc_info[i].name[KMALLOC_DMA],
- kmalloc_info[i].size,
- SLAB_CACHE_DMA | flags, 0,
- kmalloc_info[i].size);
- }
- }
- #endif
- }
- #endif /* !CONFIG_SLOB */
- gfp_t kmalloc_fix_flags(gfp_t flags)
- {
- gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK;
- flags &= ~GFP_SLAB_BUG_MASK;
- pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n",
- invalid_mask, &invalid_mask, flags, &flags);
- dump_stack();
- return flags;
- }
- /*
- * To avoid unnecessary overhead, we pass through large allocation requests
- * directly to the page allocator. We use __GFP_COMP, because we will need to
- * know the allocation order to free the pages properly in kfree.
- */
- void *kmalloc_order(size_t size, gfp_t flags, unsigned int order)
- {
- void *ret = NULL;
- struct page *page;
- if (unlikely(flags & GFP_SLAB_BUG_MASK))
- flags = kmalloc_fix_flags(flags);
- flags |= __GFP_COMP;
- page = alloc_pages(flags, order);
- if (likely(page)) {
- ret = page_address(page);
- mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
- PAGE_SIZE << order);
- }
- ret = kasan_kmalloc_large(ret, size, flags);
- /* As ret might get tagged, call kmemleak hook after KASAN. */
- kmemleak_alloc(ret, size, 1, flags);
- return ret;
- }
- EXPORT_SYMBOL(kmalloc_order);
- #ifdef CONFIG_TRACING
- void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
- {
- void *ret = kmalloc_order(size, flags, order);
- trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
- return ret;
- }
- EXPORT_SYMBOL(kmalloc_order_trace);
- #endif
- #ifdef CONFIG_SLAB_FREELIST_RANDOM
- /* Randomize a generic freelist */
- static void freelist_randomize(struct rnd_state *state, unsigned int *list,
- unsigned int count)
- {
- unsigned int rand;
- unsigned int i;
- for (i = 0; i < count; i++)
- list[i] = i;
- /* Fisher-Yates shuffle */
- for (i = count - 1; i > 0; i--) {
- rand = prandom_u32_state(state);
- rand %= (i + 1);
- swap(list[i], list[rand]);
- }
- }
- /* Create a random sequence per cache */
- int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
- gfp_t gfp)
- {
- struct rnd_state state;
- if (count < 2 || cachep->random_seq)
- return 0;
- cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
- if (!cachep->random_seq)
- return -ENOMEM;
- /* Get best entropy at this stage of boot */
- prandom_seed_state(&state, get_random_long());
- freelist_randomize(&state, cachep->random_seq, count);
- return 0;
- }
- /* Destroy the per-cache random freelist sequence */
- void cache_random_seq_destroy(struct kmem_cache *cachep)
- {
- kfree(cachep->random_seq);
- cachep->random_seq = NULL;
- }
- #endif /* CONFIG_SLAB_FREELIST_RANDOM */
- #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG)
- #ifdef CONFIG_SLAB
- #define SLABINFO_RIGHTS (0600)
- #else
- #define SLABINFO_RIGHTS (0400)
- #endif
- static void print_slabinfo_header(struct seq_file *m)
- {
- /*
- * Output format version, so at least we can change it
- * without _too_ many complaints.
- */
- #ifdef CONFIG_DEBUG_SLAB
- seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
- #else
- seq_puts(m, "slabinfo - version: 2.1\n");
- #endif
- seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
- seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
- seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
- #ifdef CONFIG_DEBUG_SLAB
- seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>");
- seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
- #endif
- seq_putc(m, '\n');
- }
- void *slab_start(struct seq_file *m, loff_t *pos)
- {
- mutex_lock(&slab_mutex);
- return seq_list_start(&slab_caches, *pos);
- }
- void *slab_next(struct seq_file *m, void *p, loff_t *pos)
- {
- return seq_list_next(p, &slab_caches, pos);
- }
- void slab_stop(struct seq_file *m, void *p)
- {
- mutex_unlock(&slab_mutex);
- }
- static void cache_show(struct kmem_cache *s, struct seq_file *m)
- {
- struct slabinfo sinfo;
- memset(&sinfo, 0, sizeof(sinfo));
- get_slabinfo(s, &sinfo);
- seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
- s->name, sinfo.active_objs, sinfo.num_objs, s->size,
- sinfo.objects_per_slab, (1 << sinfo.cache_order));
- seq_printf(m, " : tunables %4u %4u %4u",
- sinfo.limit, sinfo.batchcount, sinfo.shared);
- seq_printf(m, " : slabdata %6lu %6lu %6lu",
- sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail);
- slabinfo_show_stats(m, s);
- seq_putc(m, '\n');
- }
- static int slab_show(struct seq_file *m, void *p)
- {
- struct kmem_cache *s = list_entry(p, struct kmem_cache, list);
- if (p == slab_caches.next)
- print_slabinfo_header(m);
- cache_show(s, m);
- return 0;
- }
- void dump_unreclaimable_slab(void)
- {
- struct kmem_cache *s, *s2;
- struct slabinfo sinfo;
- /*
- * Here acquiring slab_mutex is risky since we don't prefer to get
- * sleep in oom path. But, without mutex hold, it may introduce a
- * risk of crash.
- * Use mutex_trylock to protect the list traverse, dump nothing
- * without acquiring the mutex.
- */
- if (!mutex_trylock(&slab_mutex)) {
- pr_warn("excessive unreclaimable slab but cannot dump stats\n");
- return;
- }
- pr_info("Unreclaimable slab info:\n");
- pr_info("Name Used Total\n");
- list_for_each_entry_safe(s, s2, &slab_caches, list) {
- if (s->flags & SLAB_RECLAIM_ACCOUNT)
- continue;
- get_slabinfo(s, &sinfo);
- if (sinfo.num_objs > 0)
- pr_info("%-17s %10luKB %10luKB\n", s->name,
- (sinfo.active_objs * s->size) / 1024,
- (sinfo.num_objs * s->size) / 1024);
- }
- mutex_unlock(&slab_mutex);
- }
- #if defined(CONFIG_MEMCG_KMEM)
- int memcg_slab_show(struct seq_file *m, void *p)
- {
- /*
- * Deprecated.
- * Please, take a look at tools/cgroup/slabinfo.py .
- */
- return 0;
- }
- #endif
- /*
- * slabinfo_op - iterator that generates /proc/slabinfo
- *
- * Output layout:
- * cache-name
- * num-active-objs
- * total-objs
- * object size
- * num-active-slabs
- * total-slabs
- * num-pages-per-slab
- * + further values on SMP and with statistics enabled
- */
- static const struct seq_operations slabinfo_op = {
- .start = slab_start,
- .next = slab_next,
- .stop = slab_stop,
- .show = slab_show,
- };
- static int slabinfo_open(struct inode *inode, struct file *file)
- {
- return seq_open(file, &slabinfo_op);
- }
- static const struct proc_ops slabinfo_proc_ops = {
- .proc_flags = PROC_ENTRY_PERMANENT,
- .proc_open = slabinfo_open,
- .proc_read = seq_read,
- .proc_write = slabinfo_write,
- .proc_lseek = seq_lseek,
- .proc_release = seq_release,
- };
- static int __init slab_proc_init(void)
- {
- proc_create("slabinfo", SLABINFO_RIGHTS, NULL, &slabinfo_proc_ops);
- return 0;
- }
- module_init(slab_proc_init);
- #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */
- static __always_inline void *__do_krealloc(const void *p, size_t new_size,
- gfp_t flags)
- {
- void *ret;
- size_t ks;
- /* Don't use instrumented ksize to allow precise KASAN poisoning. */
- if (likely(!ZERO_OR_NULL_PTR(p))) {
- if (!kasan_check_byte(p))
- return NULL;
- ks = kfence_ksize(p) ?: __ksize(p);
- } else
- ks = 0;
- /* If the object still fits, repoison it precisely. */
- if (ks >= new_size) {
- p = kasan_krealloc((void *)p, new_size, flags);
- return (void *)p;
- }
- ret = kmalloc_track_caller(new_size, flags);
- if (ret && p) {
- /* Disable KASAN checks as the object's redzone is accessed. */
- kasan_disable_current();
- memcpy(ret, kasan_reset_tag(p), ks);
- kasan_enable_current();
- }
- return ret;
- }
- /**
- * krealloc - reallocate memory. The contents will remain unchanged.
- * @p: object to reallocate memory for.
- * @new_size: how many bytes of memory are required.
- * @flags: the type of memory to allocate.
- *
- * The contents of the object pointed to are preserved up to the
- * lesser of the new and old sizes. If @p is %NULL, krealloc()
- * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a
- * %NULL pointer, the object pointed to is freed.
- *
- * Return: pointer to the allocated memory or %NULL in case of error
- */
- void *krealloc(const void *p, size_t new_size, gfp_t flags)
- {
- void *ret;
- if (unlikely(!new_size)) {
- kfree(p);
- return ZERO_SIZE_PTR;
- }
- ret = __do_krealloc(p, new_size, flags);
- if (ret && kasan_reset_tag(p) != kasan_reset_tag(ret))
- kfree(p);
- return ret;
- }
- EXPORT_SYMBOL(krealloc);
- /**
- * kfree_sensitive - Clear sensitive information in memory before freeing
- * @p: object to free memory of
- *
- * The memory of the object @p points to is zeroed before freed.
- * If @p is %NULL, kfree_sensitive() does nothing.
- *
- * Note: this function zeroes the whole allocated buffer which can be a good
- * deal bigger than the requested buffer size passed to kmalloc(). So be
- * careful when using this function in performance sensitive code.
- */
- void kfree_sensitive(const void *p)
- {
- size_t ks;
- void *mem = (void *)p;
- ks = ksize(mem);
- if (ks)
- memzero_explicit(mem, ks);
- kfree(mem);
- }
- EXPORT_SYMBOL(kfree_sensitive);
- /**
- * ksize - get the actual amount of memory allocated for a given object
- * @objp: Pointer to the object
- *
- * kmalloc may internally round up allocations and return more memory
- * than requested. ksize() can be used to determine the actual amount of
- * memory allocated. The caller may use this additional memory, even though
- * a smaller amount of memory was initially specified with the kmalloc call.
- * The caller must guarantee that objp points to a valid object previously
- * allocated with either kmalloc() or kmem_cache_alloc(). The object
- * must not be freed during the duration of the call.
- *
- * Return: size of the actual memory used by @objp in bytes
- */
- size_t ksize(const void *objp)
- {
- size_t size;
- /*
- * We need to first check that the pointer to the object is valid, and
- * only then unpoison the memory. The report printed from ksize() is
- * more useful, then when it's printed later when the behaviour could
- * be undefined due to a potential use-after-free or double-free.
- *
- * We use kasan_check_byte(), which is supported for the hardware
- * tag-based KASAN mode, unlike kasan_check_read/write().
- *
- * If the pointed to memory is invalid, we return 0 to avoid users of
- * ksize() writing to and potentially corrupting the memory region.
- *
- * We want to perform the check before __ksize(), to avoid potentially
- * crashing in __ksize() due to accessing invalid metadata.
- */
- if (unlikely(ZERO_OR_NULL_PTR(objp)) || !kasan_check_byte(objp))
- return 0;
- size = kfence_ksize(objp) ?: __ksize(objp);
- /*
- * We assume that ksize callers could use whole allocated area,
- * so we need to unpoison this area.
- */
- kasan_unpoison_range(objp, size);
- return size;
- }
- EXPORT_SYMBOL(ksize);
- /* Tracepoints definitions. */
- EXPORT_TRACEPOINT_SYMBOL(kmalloc);
- EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
- EXPORT_TRACEPOINT_SYMBOL(kmalloc_node);
- EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node);
- EXPORT_TRACEPOINT_SYMBOL(kfree);
- EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
- int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
- {
- if (__should_failslab(s, gfpflags))
- return -ENOMEM;
- return 0;
- }
- ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
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