Contributors: 97
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Christoph Lameter |
554 |
11.89% |
28 |
11.43% |
| Roman Gushchin |
400 |
8.58% |
8 |
3.27% |
| Kees Cook |
351 |
7.53% |
6 |
2.45% |
| Paul E. McKenney |
261 |
5.60% |
4 |
1.63% |
| Vlastimil Babka |
212 |
4.55% |
20 |
8.16% |
| Glauber de Oliveira Costa |
198 |
4.25% |
7 |
2.86% |
| Ruiqi Gong |
180 |
3.86% |
1 |
0.41% |
| Thomas Garnier |
179 |
3.84% |
2 |
0.82% |
| Vladimir Davydov |
176 |
3.78% |
16 |
6.53% |
| Pengfei Li |
139 |
2.98% |
2 |
0.82% |
| JoonSoo Kim |
133 |
2.85% |
2 |
0.82% |
| Catalin Marinas |
126 |
2.70% |
4 |
1.63% |
| Pekka J Enberg |
122 |
2.62% |
3 |
1.22% |
| Christian Brauner |
109 |
2.34% |
6 |
2.45% |
| Koichiro Den |
104 |
2.23% |
1 |
0.41% |
| Waiman Long |
99 |
2.12% |
5 |
2.04% |
| Yang Shi |
96 |
2.06% |
1 |
0.41% |
| Alexey Dobriyan |
80 |
1.72% |
15 |
6.12% |
| Marco Elver |
72 |
1.54% |
5 |
2.04% |
| HyeonggonYoo |
71 |
1.52% |
4 |
1.63% |
| Namhyung Kim |
69 |
1.48% |
1 |
0.41% |
| Matt Mackall |
68 |
1.46% |
1 |
0.41% |
| Pedro Falcato |
57 |
1.22% |
1 |
0.41% |
| Al Viro |
54 |
1.16% |
2 |
0.82% |
| Tejun Heo |
52 |
1.12% |
3 |
1.22% |
| Gavin Guo |
49 |
1.05% |
1 |
0.41% |
| Maninder Singh |
49 |
1.05% |
1 |
0.41% |
| Shuah Khan |
44 |
0.94% |
1 |
0.41% |
| Rafael Aquini |
36 |
0.77% |
2 |
0.82% |
| Long Li |
36 |
0.77% |
1 |
0.41% |
| Andrey Ryabinin |
30 |
0.64% |
2 |
0.82% |
| David Windsor |
29 |
0.62% |
1 |
0.41% |
| Linus Torvalds (pre-git) |
29 |
0.62% |
8 |
3.27% |
| Johannes Weiner |
25 |
0.54% |
2 |
0.82% |
| Feng Tang |
21 |
0.45% |
3 |
1.22% |
| 권오훈 |
21 |
0.45% |
1 |
0.41% |
| Alexander Potapenko |
21 |
0.45% |
4 |
1.63% |
| David Laight |
20 |
0.43% |
1 |
0.41% |
| Aaro Koskinen |
16 |
0.34% |
1 |
0.41% |
| Jann Horn |
14 |
0.30% |
1 |
0.41% |
| Wanpeng Li |
14 |
0.30% |
2 |
0.82% |
| Eduard - Gabriel Munteanu |
13 |
0.28% |
1 |
0.41% |
| Matthew Wilcox |
13 |
0.28% |
3 |
1.22% |
| Hyunmin Lee |
13 |
0.28% |
1 |
0.41% |
| Zhen Lei |
12 |
0.26% |
2 |
0.82% |
| Oliver Glitta |
12 |
0.26% |
1 |
0.41% |
| Christoph Hellwig |
12 |
0.26% |
2 |
0.82% |
| Daniel Sanders |
9 |
0.19% |
1 |
0.41% |
| Byongho Lee |
9 |
0.19% |
1 |
0.41% |
| Sebastian Andrzej Siewior |
8 |
0.17% |
1 |
0.41% |
| gumingtao |
8 |
0.17% |
1 |
0.41% |
| Peter Collingbourne |
7 |
0.15% |
1 |
0.41% |
| William Kucharski |
7 |
0.15% |
1 |
0.41% |
| Zheng Yejian |
7 |
0.15% |
1 |
0.41% |
| Petr Tesarik |
7 |
0.15% |
1 |
0.41% |
| Linus Torvalds |
6 |
0.13% |
2 |
0.82% |
| Pavel Emelyanov |
6 |
0.13% |
1 |
0.41% |
| Song Muchun |
5 |
0.11% |
2 |
0.82% |
| Nicholas Piggin |
4 |
0.09% |
1 |
0.41% |
| Miaohe Lin |
4 |
0.09% |
1 |
0.41% |
| Manfred Spraul |
4 |
0.09% |
1 |
0.41% |
| Mike Kravetz |
4 |
0.09% |
1 |
0.41% |
| Faiyaz Mohammed |
4 |
0.09% |
1 |
0.41% |
| Xiaolei Wang |
4 |
0.09% |
1 |
0.41% |
| Andrzej Hajda |
4 |
0.09% |
1 |
0.41% |
| Andrew Morton |
4 |
0.09% |
2 |
0.82% |
| Randy Dunlap |
3 |
0.06% |
1 |
0.41% |
| Balbir Singh |
3 |
0.06% |
1 |
0.41% |
| Arnd Bergmann |
3 |
0.06% |
1 |
0.41% |
| Dave Hansen |
3 |
0.06% |
1 |
0.41% |
| Yan Zhen |
3 |
0.06% |
1 |
0.41% |
| Martin KaFai Lau |
3 |
0.06% |
1 |
0.41% |
| Vasily Averin |
3 |
0.06% |
1 |
0.41% |
| Shakeel Butt |
3 |
0.06% |
1 |
0.41% |
| Steven Rostedt |
3 |
0.06% |
1 |
0.41% |
| Yasunori Goto |
3 |
0.06% |
1 |
0.41% |
| Jesper Dangaard Brouer |
3 |
0.06% |
1 |
0.41% |
| Xiongwei Song |
2 |
0.04% |
1 |
0.41% |
| Joe Perches |
2 |
0.04% |
2 |
0.82% |
| Hugh Dickins |
2 |
0.04% |
1 |
0.41% |
| Andrey Konovalov |
2 |
0.04% |
2 |
0.82% |
| Arnaldo Carvalho de Melo |
2 |
0.04% |
1 |
0.41% |
| David Keisar Schmidt |
2 |
0.04% |
1 |
0.41% |
| Greg Kroah-Hartman |
1 |
0.02% |
1 |
0.41% |
| Quanfa Fu |
1 |
0.02% |
1 |
0.41% |
| Lukas Bulwahn |
1 |
0.02% |
1 |
0.41% |
| Ezequiel García |
1 |
0.02% |
1 |
0.41% |
| Hui Su |
1 |
0.02% |
1 |
0.41% |
| Denis Kirjanov |
1 |
0.02% |
1 |
0.41% |
| Keith Owens |
1 |
0.02% |
1 |
0.41% |
| Helge Deller |
1 |
0.02% |
1 |
0.41% |
| Mike Rapoport |
1 |
0.02% |
1 |
0.41% |
| Mikulas Patocka |
1 |
0.02% |
1 |
0.41% |
| Geert Uytterhoeven |
1 |
0.02% |
1 |
0.41% |
| Nathan Chancellor |
1 |
0.02% |
1 |
0.41% |
| ye xingchen |
1 |
0.02% |
1 |
0.41% |
| Nicolas Boichat |
1 |
0.02% |
1 |
0.41% |
| Total |
4661 |
|
245 |
|
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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/dma-mapping.h>
#include <linux/swiotlb.h>
#include <linux/proc_fs.h>
#include <linux/debugfs.h>
#include <linux/kmemleak.h>
#include <linux/kasan.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <linux/memcontrol.h>
#include <linux/stackdepot.h>
#include "internal.h"
#include "slab.h"
#define CREATE_TRACE_POINTS
#include <trace/events/kmem.h>
enum slab_state slab_state;
LIST_HEAD(slab_caches);
DEFINE_MUTEX(slab_mutex);
struct kmem_cache *kmem_cache;
/*
* 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 | SLAB_NO_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;
}
static int __init setup_slab_merge(char *str)
{
slab_nomerge = false;
return 1;
}
__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
__setup_param("slub_merge", slub_merge, setup_slab_merge, 0);
__setup("slab_nomerge", setup_slab_nomerge);
__setup("slab_merge", setup_slab_merge);
/*
* 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 bool kmem_cache_is_duplicate_name(const char *name)
{
struct kmem_cache *s;
list_for_each_entry(s, &slab_caches, list) {
if (!strcmp(s->name, name))
return true;
}
return false;
}
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;
}
/* Duplicate names will confuse slabtop, et al */
WARN(kmem_cache_is_duplicate_name(name),
"kmem_cache of name '%s' already exists\n", name);
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
/*
* 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);
}
align = max(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;
#ifdef CONFIG_HARDENED_USERCOPY
if (s->usersize)
return 1;
#endif
/*
* 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;
flags = kmem_cache_flags(flags, name);
if (flags & SLAB_NEVER_MERGE)
return NULL;
size = ALIGN(size, sizeof(void *));
align = calculate_alignment(flags, align, size);
size = ALIGN(size, align);
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;
return s;
}
return NULL;
}
static struct kmem_cache *create_cache(const char *name,
unsigned int object_size,
struct kmem_cache_args *args,
slab_flags_t flags)
{
struct kmem_cache *s;
int err;
/* If a custom freelist pointer is requested make sure it's sane. */
err = -EINVAL;
if (args->use_freeptr_offset &&
(args->freeptr_offset >= object_size ||
!(flags & SLAB_TYPESAFE_BY_RCU) ||
!IS_ALIGNED(args->freeptr_offset, __alignof__(freeptr_t))))
goto out;
err = -ENOMEM;
s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
if (!s)
goto out;
err = do_kmem_cache_create(s, name, object_size, args, flags);
if (err)
goto out_free_cache;
s->refcount = 1;
list_add(&s->list, &slab_caches);
return s;
out_free_cache:
kmem_cache_free(kmem_cache, s);
out:
return ERR_PTR(err);
}
/**
* __kmem_cache_create_args - Create a kmem cache.
* @name: A string which is used in /proc/slabinfo to identify this cache.
* @object_size: The size of objects to be created in this cache.
* @args: Additional arguments for the cache creation (see
* &struct kmem_cache_args).
* @flags: See the desriptions of individual flags. The common ones are listed
* in the description below.
*
* Not to be called directly, use the kmem_cache_create() wrapper with the same
* parameters.
*
* Commonly used @flags:
*
* &SLAB_ACCOUNT - Account allocations to memcg.
*
* &SLAB_HWCACHE_ALIGN - Align objects on cache line boundaries.
*
* &SLAB_RECLAIM_ACCOUNT - Objects are reclaimable.
*
* &SLAB_TYPESAFE_BY_RCU - Slab page (not individual objects) freeing delayed
* by a grace period - see the full description before using.
*
* Context: Cannot be called within a interrupt, but can be interrupted.
*
* Return: a pointer to the cache on success, NULL on failure.
*/
struct kmem_cache *__kmem_cache_create_args(const char *name,
unsigned int object_size,
struct kmem_cache_args *args,
slab_flags_t flags)
{
struct kmem_cache *s = NULL;
const char *cache_name;
int err;
#ifdef CONFIG_SLUB_DEBUG
/*
* If no slab_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.
* It's also possible that this is the first cache created with
* SLAB_STORE_USER and we should init stack_depot for it.
*/
if (flags & SLAB_DEBUG_FLAGS)
static_branch_enable(&slub_debug_enabled);
if (flags & SLAB_STORE_USER)
stack_depot_init();
#endif
mutex_lock(&slab_mutex);
err = kmem_cache_sanity_check(name, object_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 (!IS_ENABLED(CONFIG_HARDENED_USERCOPY) ||
WARN_ON(!args->usersize && args->useroffset) ||
WARN_ON(object_size < args->usersize ||
object_size - args->usersize < args->useroffset))
args->usersize = args->useroffset = 0;
if (!args->usersize)
s = __kmem_cache_alias(name, object_size, args->align, flags,
args->ctor);
if (s)
goto out_unlock;
cache_name = kstrdup_const(name, GFP_KERNEL);
if (!cache_name) {
err = -ENOMEM;
goto out_unlock;
}
args->align = calculate_alignment(flags, args->align, object_size);
s = create_cache(cache_name, object_size, args, flags);
if (IS_ERR(s)) {
err = PTR_ERR(s);
kfree_const(cache_name);
}
out_unlock:
mutex_unlock(&slab_mutex);
if (err) {
if (flags & SLAB_PANIC)
panic("%s: Failed to create slab '%s'. Error %d\n",
__func__, name, err);
else {
pr_warn("%s(%s) failed with error %d\n",
__func__, name, err);
dump_stack();
}
return NULL;
}
return s;
}
EXPORT_SYMBOL(__kmem_cache_create_args);
static struct kmem_cache *kmem_buckets_cache __ro_after_init;
/**
* kmem_buckets_create - Create a set of caches that handle dynamic sized
* allocations via kmem_buckets_alloc()
* @name: A prefix string which is used in /proc/slabinfo to identify this
* cache. The individual caches with have their sizes as the suffix.
* @flags: SLAB flags (see kmem_cache_create() for details).
* @useroffset: Starting offset within an allocation that may be copied
* to/from userspace.
* @usersize: How many bytes, starting at @useroffset, may be copied
* to/from userspace.
* @ctor: A constructor for the objects, run when new allocations are made.
*
* Cannot be called within an interrupt, but can be interrupted.
*
* Return: a pointer to the cache on success, NULL on failure. When
* CONFIG_SLAB_BUCKETS is not enabled, ZERO_SIZE_PTR is returned, and
* subsequent calls to kmem_buckets_alloc() will fall back to kmalloc().
* (i.e. callers only need to check for NULL on failure.)
*/
kmem_buckets *kmem_buckets_create(const char *name, slab_flags_t flags,
unsigned int useroffset,
unsigned int usersize,
void (*ctor)(void *))
{
unsigned long mask = 0;
unsigned int idx;
kmem_buckets *b;
BUILD_BUG_ON(ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]) > BITS_PER_LONG);
/*
* When the separate buckets API is not built in, just return
* a non-NULL value for the kmem_buckets pointer, which will be
* unused when performing allocations.
*/
if (!IS_ENABLED(CONFIG_SLAB_BUCKETS))
return ZERO_SIZE_PTR;
if (WARN_ON(!kmem_buckets_cache))
return NULL;
b = kmem_cache_alloc(kmem_buckets_cache, GFP_KERNEL|__GFP_ZERO);
if (WARN_ON(!b))
return NULL;
flags |= SLAB_NO_MERGE;
for (idx = 0; idx < ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]); idx++) {
char *short_size, *cache_name;
unsigned int cache_useroffset, cache_usersize;
unsigned int size, aligned_idx;
if (!kmalloc_caches[KMALLOC_NORMAL][idx])
continue;
size = kmalloc_caches[KMALLOC_NORMAL][idx]->object_size;
if (!size)
continue;
short_size = strchr(kmalloc_caches[KMALLOC_NORMAL][idx]->name, '-');
if (WARN_ON(!short_size))
goto fail;
if (useroffset >= size) {
cache_useroffset = 0;
cache_usersize = 0;
} else {
cache_useroffset = useroffset;
cache_usersize = min(size - cache_useroffset, usersize);
}
aligned_idx = __kmalloc_index(size, false);
if (!(*b)[aligned_idx]) {
cache_name = kasprintf(GFP_KERNEL, "%s-%s", name, short_size + 1);
if (WARN_ON(!cache_name))
goto fail;
(*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size,
0, flags, cache_useroffset,
cache_usersize, ctor);
kfree(cache_name);
if (WARN_ON(!(*b)[aligned_idx]))
goto fail;
set_bit(aligned_idx, &mask);
}
if (idx != aligned_idx)
(*b)[idx] = (*b)[aligned_idx];
}
return b;
fail:
for_each_set_bit(idx, &mask, ARRAY_SIZE(kmalloc_caches[KMALLOC_NORMAL]))
kmem_cache_destroy((*b)[idx]);
kmem_cache_free(kmem_buckets_cache, b);
return NULL;
}
EXPORT_SYMBOL(kmem_buckets_create);
/*
* For a given kmem_cache, kmem_cache_destroy() should only be called
* once or there will be a use-after-free problem. The actual deletion
* and release of the kobject does not need slab_mutex or cpu_hotplug_lock
* protection. So they are now done without holding those locks.
*/
static void kmem_cache_release(struct kmem_cache *s)
{
kfence_shutdown_cache(s);
if (__is_defined(SLAB_SUPPORTS_SYSFS) && slab_state >= FULL)
sysfs_slab_release(s);
else
slab_kmem_cache_release(s);
}
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) || !kasan_check_byte(s))
return;
/* in-flight kfree_rcu()'s may include objects from our cache */
kvfree_rcu_barrier();
if (IS_ENABLED(CONFIG_SLUB_RCU_DEBUG) &&
(s->flags & SLAB_TYPESAFE_BY_RCU)) {
/*
* Under CONFIG_SLUB_RCU_DEBUG, when objects in a
* SLAB_TYPESAFE_BY_RCU slab are freed, SLUB will internally
* defer their freeing with call_rcu().
* Wait for such call_rcu() invocations here before actually
* destroying the cache.
*
* It doesn't matter that we haven't looked at the slab refcount
* yet - slabs with SLAB_TYPESAFE_BY_RCU can't be merged, so
* the refcount should be 1 here.
*/
rcu_barrier();
}
cpus_read_lock();
mutex_lock(&slab_mutex);
s->refcount--;
if (s->refcount) {
mutex_unlock(&slab_mutex);
cpus_read_unlock();
return;
}
/* free asan quarantined objects */
kasan_cache_shutdown(s);
err = __kmem_cache_shutdown(s);
if (!slab_in_kunit_test())
WARN(err, "%s %s: Slab cache still has objects when called from %pS",
__func__, s->name, (void *)_RET_IP_);
list_del(&s->list);
mutex_unlock(&slab_mutex);
cpus_read_unlock();
if (slab_state >= FULL)
sysfs_slab_unlink(s);
debugfs_slab_release(s);
if (err)
return;
if (s->flags & SLAB_TYPESAFE_BY_RCU)
rcu_barrier();
kmem_cache_release(s);
}
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)
{
kasan_cache_shrink(cachep);
return __kmem_cache_shrink(cachep);
}
EXPORT_SYMBOL(kmem_cache_shrink);
bool slab_is_available(void)
{
return slab_state >= UP;
}
#ifdef CONFIG_PRINTK
static void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
{
if (__kfence_obj_info(kpp, object, slab))
return;
__kmem_obj_info(kpp, object, slab);
}
/**
* kmem_dump_obj - Print available slab provenance information
* @object: slab object for which to find provenance information.
*
* This function uses pr_cont(), so that the caller is expected to have
* printed out whatever preamble is appropriate. The provenance information
* depends on the type of object and on how much debugging is enabled.
* For a slab-cache object, the fact that it is a slab object is printed,
* and, if available, the slab name, return address, and stack trace from
* the allocation and last free path of that object.
*
* Return: %true if the pointer is to a not-yet-freed object from
* kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer
* is to an already-freed object, and %false otherwise.
*/
bool kmem_dump_obj(void *object)
{
char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc";
int i;
struct slab *slab;
unsigned long ptroffset;
struct kmem_obj_info kp = { };
/* Some arches consider ZERO_SIZE_PTR to be a valid address. */
if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
return false;
slab = virt_to_slab(object);
if (!slab)
return false;
kmem_obj_info(&kp, object, slab);
if (kp.kp_slab_cache)
pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name);
else
pr_cont(" slab%s", cp);
if (is_kfence_address(object))
pr_cont(" (kfence)");
if (kp.kp_objp)
pr_cont(" start %px", kp.kp_objp);
if (kp.kp_data_offset)
pr_cont(" data offset %lu", kp.kp_data_offset);
if (kp.kp_objp) {
ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset;
pr_cont(" pointer offset %lu", ptroffset);
}
if (kp.kp_slab_cache && kp.kp_slab_cache->object_size)
pr_cont(" size %u", kp.kp_slab_cache->object_size);
if (kp.kp_ret)
pr_cont(" allocated at %pS\n", kp.kp_ret);
else
pr_cont("\n");
for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) {
if (!kp.kp_stack[i])
break;
pr_info(" %pS\n", kp.kp_stack[i]);
}
if (kp.kp_free_stack[0])
pr_cont(" Free path:\n");
for (i = 0; i < ARRAY_SIZE(kp.kp_free_stack); i++) {
if (!kp.kp_free_stack[i])
break;
pr_info(" %pS\n", kp.kp_free_stack[i]);
}
return true;
}
EXPORT_SYMBOL_GPL(kmem_dump_obj);
#endif
/* 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;
struct kmem_cache_args kmem_args = {};
/*
* kmalloc caches guarantee alignment of at least the largest
* power-of-two divisor of the size. For power-of-two sizes,
* it is the size itself.
*/
if (flags & SLAB_KMALLOC)
align = max(align, 1U << (ffs(size) - 1));
kmem_args.align = calculate_alignment(flags, align, size);
#ifdef CONFIG_HARDENED_USERCOPY
kmem_args.useroffset = useroffset;
kmem_args.usersize = usersize;
#endif
err = do_kmem_cache_create(s, name, size, &kmem_args, 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 */
}
static struct kmem_cache *__init create_kmalloc_cache(const char *name,
unsigned int size,
slab_flags_t flags)
{
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 | SLAB_KMALLOC, 0, size);
list_add(&s->list, &slab_caches);
s->refcount = 1;
return s;
}
kmem_buckets kmalloc_caches[NR_KMALLOC_TYPES] __ro_after_init =
{ /* initialization for https://llvm.org/pr42570 */ };
EXPORT_SYMBOL(kmalloc_caches);
#ifdef CONFIG_RANDOM_KMALLOC_CACHES
unsigned long random_kmalloc_seed __ro_after_init;
EXPORT_SYMBOL(random_kmalloc_seed);
#endif
/*
* 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.
*/
u8 kmalloc_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 */
};
size_t kmalloc_size_roundup(size_t size)
{
if (size && size <= KMALLOC_MAX_CACHE_SIZE) {
/*
* The flags don't matter since size_index is common to all.
* Neither does the caller for just getting ->object_size.
*/
return kmalloc_slab(size, NULL, GFP_KERNEL, 0)->object_size;
}
/* Above the smaller buckets, size is a multiple of page size. */
if (size && size <= KMALLOC_MAX_SIZE)
return PAGE_SIZE << get_order(size);
/*
* Return 'size' for 0 - kmalloc() returns ZERO_SIZE_PTR
* and very large size - kmalloc() may fail.
*/
return size;
}
EXPORT_SYMBOL(kmalloc_size_roundup);
#ifdef CONFIG_ZONE_DMA
#define KMALLOC_DMA_NAME(sz) .name[KMALLOC_DMA] = "dma-kmalloc-" #sz,
#else
#define KMALLOC_DMA_NAME(sz)
#endif
#ifdef CONFIG_MEMCG
#define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz,
#else
#define KMALLOC_CGROUP_NAME(sz)
#endif
#ifndef CONFIG_SLUB_TINY
#define KMALLOC_RCL_NAME(sz) .name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #sz,
#else
#define KMALLOC_RCL_NAME(sz)
#endif
#ifdef CONFIG_RANDOM_KMALLOC_CACHES
#define __KMALLOC_RANDOM_CONCAT(a, b) a ## b
#define KMALLOC_RANDOM_NAME(N, sz) __KMALLOC_RANDOM_CONCAT(KMA_RAND_, N)(sz)
#define KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 1] = "kmalloc-rnd-01-" #sz,
#define KMA_RAND_2(sz) KMA_RAND_1(sz) .name[KMALLOC_RANDOM_START + 2] = "kmalloc-rnd-02-" #sz,
#define KMA_RAND_3(sz) KMA_RAND_2(sz) .name[KMALLOC_RANDOM_START + 3] = "kmalloc-rnd-03-" #sz,
#define KMA_RAND_4(sz) KMA_RAND_3(sz) .name[KMALLOC_RANDOM_START + 4] = "kmalloc-rnd-04-" #sz,
#define KMA_RAND_5(sz) KMA_RAND_4(sz) .name[KMALLOC_RANDOM_START + 5] = "kmalloc-rnd-05-" #sz,
#define KMA_RAND_6(sz) KMA_RAND_5(sz) .name[KMALLOC_RANDOM_START + 6] = "kmalloc-rnd-06-" #sz,
#define KMA_RAND_7(sz) KMA_RAND_6(sz) .name[KMALLOC_RANDOM_START + 7] = "kmalloc-rnd-07-" #sz,
#define KMA_RAND_8(sz) KMA_RAND_7(sz) .name[KMALLOC_RANDOM_START + 8] = "kmalloc-rnd-08-" #sz,
#define KMA_RAND_9(sz) KMA_RAND_8(sz) .name[KMALLOC_RANDOM_START + 9] = "kmalloc-rnd-09-" #sz,
#define KMA_RAND_10(sz) KMA_RAND_9(sz) .name[KMALLOC_RANDOM_START + 10] = "kmalloc-rnd-10-" #sz,
#define KMA_RAND_11(sz) KMA_RAND_10(sz) .name[KMALLOC_RANDOM_START + 11] = "kmalloc-rnd-11-" #sz,
#define KMA_RAND_12(sz) KMA_RAND_11(sz) .name[KMALLOC_RANDOM_START + 12] = "kmalloc-rnd-12-" #sz,
#define KMA_RAND_13(sz) KMA_RAND_12(sz) .name[KMALLOC_RANDOM_START + 13] = "kmalloc-rnd-13-" #sz,
#define KMA_RAND_14(sz) KMA_RAND_13(sz) .name[KMALLOC_RANDOM_START + 14] = "kmalloc-rnd-14-" #sz,
#define KMA_RAND_15(sz) KMA_RAND_14(sz) .name[KMALLOC_RANDOM_START + 15] = "kmalloc-rnd-15-" #sz,
#else // CONFIG_RANDOM_KMALLOC_CACHES
#define KMALLOC_RANDOM_NAME(N, sz)
#endif
#define INIT_KMALLOC_INFO(__size, __short_size) \
{ \
.name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
KMALLOC_RCL_NAME(__short_size) \
KMALLOC_CGROUP_NAME(__short_size) \
KMALLOC_DMA_NAME(__short_size) \
KMALLOC_RANDOM_NAME(RANDOM_KMALLOC_CACHES_NR, __short_size) \
.size = __size, \
}
/*
* kmalloc_info[] is to make slab_debug=,kmalloc-xx option work at boot time.
* kmalloc_index() supports up to 2^21=2MB, so the final entry of the table is
* kmalloc-2M.
*/
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)
};
/*
* 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 ||
!is_power_of_2(KMALLOC_MIN_SIZE));
for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
unsigned int elem = size_index_elem(i);
if (elem >= ARRAY_SIZE(kmalloc_size_index))
break;
kmalloc_size_index[elem] = KMALLOC_SHIFT_LOW;
}
if (KMALLOC_MIN_SIZE >= 64) {
/*
* The 96 byte sized cache is not used if the alignment
* is 64 byte.
*/
for (i = 64 + 8; i <= 96; i += 8)
kmalloc_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)
kmalloc_size_index[size_index_elem(i)] = 8;
}
}
static unsigned int __kmalloc_minalign(void)
{
unsigned int minalign = dma_get_cache_alignment();
if (IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) &&
is_swiotlb_allocated())
minalign = ARCH_KMALLOC_MINALIGN;
return max(minalign, arch_slab_minalign());
}
static void __init
new_kmalloc_cache(int idx, enum kmalloc_cache_type type)
{
slab_flags_t flags = 0;
unsigned int minalign = __kmalloc_minalign();
unsigned int aligned_size = kmalloc_info[idx].size;
int aligned_idx = idx;
if ((KMALLOC_RECLAIM != KMALLOC_NORMAL) && (type == KMALLOC_RECLAIM)) {
flags |= SLAB_RECLAIM_ACCOUNT;
} else if (IS_ENABLED(CONFIG_MEMCG) && (type == KMALLOC_CGROUP)) {
if (mem_cgroup_kmem_disabled()) {
kmalloc_caches[type][idx] = kmalloc_caches[KMALLOC_NORMAL][idx];
return;
}
flags |= SLAB_ACCOUNT;
} else if (IS_ENABLED(CONFIG_ZONE_DMA) && (type == KMALLOC_DMA)) {
flags |= SLAB_CACHE_DMA;
}
#ifdef CONFIG_RANDOM_KMALLOC_CACHES
if (type >= KMALLOC_RANDOM_START && type <= KMALLOC_RANDOM_END)
flags |= SLAB_NO_MERGE;
#endif
/*
* If CONFIG_MEMCG is enabled, disable cache merging for
* KMALLOC_NORMAL caches.
*/
if (IS_ENABLED(CONFIG_MEMCG) && (type == KMALLOC_NORMAL))
flags |= SLAB_NO_MERGE;
if (minalign > ARCH_KMALLOC_MINALIGN) {
aligned_size = ALIGN(aligned_size, minalign);
aligned_idx = __kmalloc_index(aligned_size, false);
}
if (!kmalloc_caches[type][aligned_idx])
kmalloc_caches[type][aligned_idx] = create_kmalloc_cache(
kmalloc_info[aligned_idx].name[type],
aligned_size, flags);
if (idx != aligned_idx)
kmalloc_caches[type][idx] = kmalloc_caches[type][aligned_idx];
}
/*
* 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(void)
{
int i;
enum kmalloc_cache_type type;
/*
* Including KMALLOC_CGROUP if CONFIG_MEMCG defined
*/
for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; type++) {
/* Caches that are NOT of the two-to-the-power-of size. */
if (KMALLOC_MIN_SIZE <= 32)
new_kmalloc_cache(1, type);
if (KMALLOC_MIN_SIZE <= 64)
new_kmalloc_cache(2, type);
/* Caches that are of the two-to-the-power-of size. */
for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++)
new_kmalloc_cache(i, type);
}
#ifdef CONFIG_RANDOM_KMALLOC_CACHES
random_kmalloc_seed = get_random_u64();
#endif
/* Kmalloc array is now usable */
slab_state = UP;
if (IS_ENABLED(CONFIG_SLAB_BUCKETS))
kmem_buckets_cache = kmem_cache_create("kmalloc_buckets",
sizeof(kmem_buckets),
0, SLAB_NO_MERGE, NULL);
}
/**
* __ksize -- Report full size of underlying allocation
* @object: pointer to the object
*
* This should only be used internally to query the true size of allocations.
* It is not meant to be a way to discover the usable size of an allocation
* after the fact. Instead, use kmalloc_size_roundup(). Using memory beyond
* the originally requested allocation size may trigger KASAN, UBSAN_BOUNDS,
* and/or FORTIFY_SOURCE.
*
* Return: size of the actual memory used by @object in bytes
*/
size_t __ksize(const void *object)
{
struct folio *folio;
if (unlikely(object == ZERO_SIZE_PTR))
return 0;
folio = virt_to_folio(object);
if (unlikely(!folio_test_slab(folio))) {
if (WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE))
return 0;
if (WARN_ON(object != folio_address(folio)))
return 0;
return folio_size(folio);
}
#ifdef CONFIG_SLUB_DEBUG
skip_orig_size_check(folio_slab(folio)->slab_cache, object);
#endif
return slab_ksize(folio_slab(folio)->slab_cache);
}
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;
}
#ifdef CONFIG_SLAB_FREELIST_RANDOM
/* Randomize a generic freelist */
static void freelist_randomize(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 = get_random_u32_below(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)
{
if (count < 2 || cachep->random_seq)
return 0;
cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp);
if (!cachep->random_seq)
return -ENOMEM;
freelist_randomize(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 */
#ifdef CONFIG_SLUB_DEBUG
#define SLABINFO_RIGHTS (0400)
static void print_slabinfo_header(struct seq_file *m)
{
/*
* Output format version, so at least we can change it
* without _too_ many complaints.
*/
seq_puts(m, "slabinfo - version: 2.1\n");
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>");
seq_putc(m, '\n');
}
static void *slab_start(struct seq_file *m, loff_t *pos)
{
mutex_lock(&slab_mutex);
return seq_list_start(&slab_caches, *pos);
}
static void *slab_next(struct seq_file *m, void *p, loff_t *pos)
{
return seq_list_next(p, &slab_caches, pos);
}
static 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);
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;
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(s, &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);
}
/*
* 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_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_SLUB_DEBUG */
/**
* 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) {
kasan_unpoison_range(mem, ks);
memzero_explicit(mem, ks);
}
kfree(mem);
}
EXPORT_SYMBOL(kfree_sensitive);
size_t ksize(const void *objp)
{
/*
* We need to first check that the pointer to the object is valid.
* The KASAN 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;
return kfence_ksize(objp) ?: __ksize(objp);
}
EXPORT_SYMBOL(ksize);
#ifdef CONFIG_BPF_SYSCALL
#include <linux/btf.h>
__bpf_kfunc_start_defs();
__bpf_kfunc struct kmem_cache *bpf_get_kmem_cache(u64 addr)
{
struct slab *slab;
if (!virt_addr_valid((void *)(long)addr))
return NULL;
slab = virt_to_slab((void *)(long)addr);
return slab ? slab->slab_cache : NULL;
}
__bpf_kfunc_end_defs();
#endif /* CONFIG_BPF_SYSCALL */
/* Tracepoints definitions. */
EXPORT_TRACEPOINT_SYMBOL(kmalloc);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc);
EXPORT_TRACEPOINT_SYMBOL(kfree);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);