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slab updates for 6.13

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Merge tag 'slab-for-6.13-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - Add new slab_strict_numa boot parameter to enforce per-object memory
   policies on top of slab folio policies, for systems where saving cost
   of remote accesses is more important than minimizing slab allocation
   overhead (Christoph Lameter)

 - Fix for freeptr_offset alignment check being too strict for m68k
   (Geert Uytterhoeven)

 - krealloc() fixes for not violating __GFP_ZERO guarantees on
   krealloc() when slub_debug (redzone and object tracking) is enabled
   (Feng Tang)

 - Fix a memory leak in case sysfs registration fails for a slab cache,
   and also no longer fail to create the cache in that case (Hyeonggon
   Yoo)

 - Fix handling of detected consistency problems (due to buggy slab
   user) with slub_debug enabled, so that it does not cause further list
   corruption bugs (yuan.gao)

 - Code cleanup and kerneldocs polishing (Zhen Lei, Vlastimil Babka)

* tag 'slab-for-6.13-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  slab: Fix too strict alignment check in create_cache()
  mm/slab: Allow cache creation to proceed even if sysfs registration fails
  mm/slub: Avoid list corruption when removing a slab from the full list
  mm/slub, kunit: Add testcase for krealloc redzone and zeroing
  mm/slub: Improve redzone check and zeroing for krealloc()
  mm/slub: Consider kfence case for get_orig_size()
  SLUB: Add support for per object memory policies
  mm, slab: add kerneldocs for common SLAB_ flags
  mm/slab: remove duplicate check in create_cache()
  mm/slub: Move krealloc() and related code to slub.c
  mm/kasan: Don't store metadata inside kmalloc object when slub_debug_orig_size is on
This commit is contained in:
Linus Torvalds 2024-11-25 16:51:24 -08:00
commit e06635e26c
8 changed files with 325 additions and 137 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
Documentation/admin-guide/kernel-parameters.txt
View File

@ -6158,6 +6158,16 @@
For more information see Documentation/mm/slub.rst.
(slub_nomerge legacy name also accepted for now)
slab_strict_numa [MM]
Support memory policies on a per object level
in the slab allocator. The default is for memory
policies to be applied at the folio level when
a new folio is needed or a partial folio is
retrieved from the lists. Increases overhead
in the slab fastpaths but gains more accurate
NUMA kernel object placement which helps with slow
interconnects in NUMA systems.
slram= [HW,MTD]
smart2= [HW]

9
Documentation/mm/slub.rst
View File

@ -175,6 +175,15 @@ can be influenced by kernel parameters:
``slab_max_order`` to 0, what cause minimum possible order of
slabs allocation.
``slab_strict_numa``
Enables the application of memory policies on each
allocation. This results in more accurate placement of
objects which may result in the reduction of accesses
to remote nodes. The default is to only apply memory
policies at the folio level when a new folio is acquired
or a folio is retrieved from the lists. Enabling this
option reduces the fastpath performance of the slab allocator.
SLUB Debug output
=================

60
include/linux/slab.h
View File

@ -77,7 +77,17 @@ enum _slab_flag_bits {
#define SLAB_POISON __SLAB_FLAG_BIT(_SLAB_POISON)
/* Indicate a kmalloc slab */
#define SLAB_KMALLOC __SLAB_FLAG_BIT(_SLAB_KMALLOC)
/* Align objs on cache lines */
/**
* define SLAB_HWCACHE_ALIGN - Align objects on cache line boundaries.
*
* Sufficiently large objects are aligned on cache line boundary. For object
* size smaller than a half of cache line size, the alignment is on the half of
* cache line size. In general, if object size is smaller than 1/2^n of cache
* line size, the alignment is adjusted to 1/2^n.
*
* If explicit alignment is also requested by the respective
* &struct kmem_cache_args field, the greater of both is alignments is applied.
*/
#define SLAB_HWCACHE_ALIGN __SLAB_FLAG_BIT(_SLAB_HWCACHE_ALIGN)
/* Use GFP_DMA memory */
#define SLAB_CACHE_DMA __SLAB_FLAG_BIT(_SLAB_CACHE_DMA)
@ -87,8 +97,8 @@ enum _slab_flag_bits {
#define SLAB_STORE_USER __SLAB_FLAG_BIT(_SLAB_STORE_USER)
/* Panic if kmem_cache_create() fails */
#define SLAB_PANIC __SLAB_FLAG_BIT(_SLAB_PANIC)
/*
* SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
/**
* define SLAB_TYPESAFE_BY_RCU - **WARNING** READ THIS!
*
* This delays freeing the SLAB page by a grace period, it does _NOT_
* delay object freeing. This means that if you do kmem_cache_free()
@ -99,20 +109,22 @@ enum _slab_flag_bits {
* stays valid, the trick to using this is relying on an independent
* object validation pass. Something like:
*
* begin:
* rcu_read_lock();
* obj = lockless_lookup(key);
* if (obj) {
* if (!try_get_ref(obj)) // might fail for free objects
* rcu_read_unlock();
* goto begin;
* ::
*
* if (obj->key != key) { // not the object we expected
* put_ref(obj);
* rcu_read_unlock();
* goto begin;
* }
* }
* begin:
* rcu_read_lock();
* obj = lockless_lookup(key);
* if (obj) {
* if (!try_get_ref(obj)) // might fail for free objects
* rcu_read_unlock();
* goto begin;
*
* if (obj->key != key) { // not the object we expected
* put_ref(obj);
* rcu_read_unlock();
* goto begin;
* }
* }
* rcu_read_unlock();
*
* This is useful if we need to approach a kernel structure obliquely,
@ -137,7 +149,6 @@ enum _slab_flag_bits {
*
* Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.
*/
/* Defer freeing slabs to RCU */
#define SLAB_TYPESAFE_BY_RCU __SLAB_FLAG_BIT(_SLAB_TYPESAFE_BY_RCU)
/* Trace allocations and frees */
#define SLAB_TRACE __SLAB_FLAG_BIT(_SLAB_TRACE)
@ -170,7 +181,12 @@ enum _slab_flag_bits {
#else
# define SLAB_FAILSLAB __SLAB_FLAG_UNUSED
#endif
/* Account to memcg */
/**
* define SLAB_ACCOUNT - Account allocations to memcg.
*
* All object allocations from this cache will be memcg accounted, regardless of
* __GFP_ACCOUNT being or not being passed to individual allocations.
*/
#ifdef CONFIG_MEMCG
# define SLAB_ACCOUNT __SLAB_FLAG_BIT(_SLAB_ACCOUNT)
#else
@ -197,7 +213,13 @@ enum _slab_flag_bits {
#endif
/* The following flags affect the page allocator grouping pages by mobility */
/* Objects are reclaimable */
/**
* define SLAB_RECLAIM_ACCOUNT - Objects are reclaimable.
*
* Use this flag for caches that have an associated shrinker. As a result, slab
* pages are allocated with __GFP_RECLAIMABLE, which affects grouping pages by
* mobility, and are accounted in SReclaimable counter in /proc/meminfo
*/
#ifndef CONFIG_SLUB_TINY
#define SLAB_RECLAIM_ACCOUNT __SLAB_FLAG_BIT(_SLAB_RECLAIM_ACCOUNT)
#else

42
lib/slub_kunit.c
View File

@ -192,6 +192,47 @@ static void test_leak_destroy(struct kunit *test)
KUNIT_EXPECT_EQ(test, 2, slab_errors);
}
static void test_krealloc_redzone_zeroing(struct kunit *test)
{
u8 *p;
int i;
struct kmem_cache *s = test_kmem_cache_create("TestSlub_krealloc", 64,
SLAB_KMALLOC|SLAB_STORE_USER|SLAB_RED_ZONE);
p = alloc_hooks(__kmalloc_cache_noprof(s, GFP_KERNEL, 48));
memset(p, 0xff, 48);
kasan_disable_current();
OPTIMIZER_HIDE_VAR(p);
/* Test shrink */
p = krealloc(p, 40, GFP_KERNEL | __GFP_ZERO);
for (i = 40; i < 64; i++)
KUNIT_EXPECT_EQ(test, p[i], SLUB_RED_ACTIVE);
/* Test grow within the same 64B kmalloc object */
p = krealloc(p, 56, GFP_KERNEL | __GFP_ZERO);
for (i = 40; i < 56; i++)
KUNIT_EXPECT_EQ(test, p[i], 0);
for (i = 56; i < 64; i++)
KUNIT_EXPECT_EQ(test, p[i], SLUB_RED_ACTIVE);
validate_slab_cache(s);
KUNIT_EXPECT_EQ(test, 0, slab_errors);
memset(p, 0xff, 56);
/* Test grow with allocating a bigger 128B object */
p = krealloc(p, 112, GFP_KERNEL | __GFP_ZERO);
for (i = 0; i < 56; i++)
KUNIT_EXPECT_EQ(test, p[i], 0xff);
for (i = 56; i < 112; i++)
KUNIT_EXPECT_EQ(test, p[i], 0);
kfree(p);
kasan_enable_current();
kmem_cache_destroy(s);
}
static int test_init(struct kunit *test)
{
slab_errors = 0;
@ -214,6 +255,7 @@ static struct kunit_case test_cases[] = {
KUNIT_CASE(test_kmalloc_redzone_access),
KUNIT_CASE(test_kfree_rcu),
KUNIT_CASE(test_leak_destroy),
KUNIT_CASE(test_krealloc_redzone_zeroing),
{}
};

7
mm/kasan/generic.c
View File

@ -392,9 +392,12 @@ void kasan_cache_create(struct kmem_cache *cache, unsigned int *size,
* 1. Object is SLAB_TYPESAFE_BY_RCU, which means that it can
* be touched after it was freed, or
* 2. Object has a constructor, which means it's expected to
* retain its content until the next allocation.
* retain its content until the next allocation, or
* 3. It is from a kmalloc cache which enables the debug option
* to store original size.
*/
if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor) {
if ((cache->flags & SLAB_TYPESAFE_BY_RCU) || cache->ctor ||
slub_debug_orig_size(cache)) {
cache->kasan_info.free_meta_offset = *size;
*size += sizeof(struct kasan_free_meta);
goto free_meta_added;

11
mm/slab.h
View File

@ -73,6 +73,11 @@ struct slab {
struct {
unsigned inuse:16;
unsigned objects:15;
/*
* If slab debugging is enabled then the
* frozen bit can be reused to indicate
* that the slab was corrupted
*/
unsigned frozen:1;
};
};
@ -695,6 +700,12 @@ void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
void __check_heap_object(const void *ptr, unsigned long n,
const struct slab *slab, bool to_user);
static inline bool slub_debug_orig_size(struct kmem_cache *s)
{
return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
(s->flags & SLAB_KMALLOC));
}
#ifdef CONFIG_SLUB_DEBUG
void skip_orig_size_check(struct kmem_cache *s, const void *object);
#endif

103
mm/slab_common.c
View File

@ -222,15 +222,12 @@ static struct kmem_cache *create_cache(const char *name,
struct kmem_cache *s;
int err;
if (WARN_ON(args->useroffset + args->usersize > object_size))
args->useroffset = args->usersize = 0;
/* 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, sizeof(freeptr_t))))
!IS_ALIGNED(args->freeptr_offset, __alignof__(freeptr_t))))
goto out;
err = -ENOMEM;
@ -257,11 +254,23 @@ out:
* @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 %SLAB_* flags for an explanation of individual @flags.
* @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.
@ -1199,90 +1208,6 @@ module_init(slab_proc_init);
#endif /* CONFIG_SLUB_DEBUG */
static __always_inline __realloc_size(2) void *
__do_krealloc(const void *p, size_t new_size, gfp_t flags)
{
void *ret;
size_t ks;
/* Check for double-free before calling ksize. */
if (likely(!ZERO_OR_NULL_PTR(p))) {
if (!kasan_check_byte(p))
return NULL;
ks = ksize(p);
} else
ks = 0;
/* If the object still fits, repoison it precisely. */
if (ks >= new_size) {
/* Zero out spare memory. */
if (want_init_on_alloc(flags)) {
kasan_disable_current();
memset(kasan_reset_tag(p) + new_size, 0, ks - new_size);
kasan_enable_current();
}
p = kasan_krealloc((void *)p, new_size, flags);
return (void *)p;
}
ret = kmalloc_node_track_caller_noprof(new_size, flags, NUMA_NO_NODE, _RET_IP_);
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.
*
* 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.
*
* If __GFP_ZERO logic is requested, callers must ensure that, starting with the
* initial memory allocation, every subsequent call to this API for the same
* memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
* __GFP_ZERO is not fully honored by this API.
*
* This is the case, since krealloc() only knows about the bucket size of an
* allocation (but not the exact size it was allocated with) and hence
* implements the following semantics for shrinking and growing buffers with
* __GFP_ZERO.
*
* new bucket
* 0 size size
* |--------|----------------|
* | keep | zero |
*
* In any case, the contents of the object pointed to are preserved up to the
* lesser of the new and old sizes.
*
* Return: pointer to the allocated memory or %NULL in case of error
*/
void *krealloc_noprof(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_noprof);
/**
* kfree_sensitive - Clear sensitive information in memory before freeing
* @p: object to free memory of

220
mm/slub.c
View File

@ -218,6 +218,10 @@ DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
#endif
#endif /* CONFIG_SLUB_DEBUG */
#ifdef CONFIG_NUMA
static DEFINE_STATIC_KEY_FALSE(strict_numa);
#endif
/* Structure holding parameters for get_partial() call chain */
struct partial_context {
gfp_t flags;
@ -230,12 +234,6 @@ static inline bool kmem_cache_debug(struct kmem_cache *s)
return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
}
static inline bool slub_debug_orig_size(struct kmem_cache *s)
{
return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
(s->flags & SLAB_KMALLOC));
}
void *fixup_red_left(struct kmem_cache *s, void *p)
{
if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
@ -760,21 +758,10 @@ static inline void set_orig_size(struct kmem_cache *s,
void *object, unsigned int orig_size)
{
void *p = kasan_reset_tag(object);
unsigned int kasan_meta_size;
if (!slub_debug_orig_size(s))
return;
/*
* KASAN can save its free meta data inside of the object at offset 0.
* If this meta data size is larger than 'orig_size', it will overlap
* the data redzone in [orig_size+1, object_size]. Thus, we adjust
* 'orig_size' to be as at least as big as KASAN's meta data.
*/
kasan_meta_size = kasan_metadata_size(s, true);
if (kasan_meta_size > orig_size)
orig_size = kasan_meta_size;
p += get_info_end(s);
p += sizeof(struct track) * 2;
@ -785,6 +772,9 @@ static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
{
void *p = kasan_reset_tag(object);
if (is_kfence_address(object))
return kfence_ksize(object);
if (!slub_debug_orig_size(s))
return s->object_size;
@ -1423,6 +1413,11 @@ static int check_slab(struct kmem_cache *s, struct slab *slab)
slab->inuse, slab->objects);
return 0;
}
if (slab->frozen) {
slab_err(s, slab, "Slab disabled since SLUB metadata consistency check failed");
return 0;
}
/* Slab_pad_check fixes things up after itself */
slab_pad_check(s, slab);
return 1;
@ -1603,6 +1598,7 @@ bad:
slab_fix(s, "Marking all objects used");
slab->inuse = slab->objects;
slab->freelist = NULL;
slab->frozen = 1; /* mark consistency-failed slab as frozen */
}
return false;
}
@ -2744,7 +2740,8 @@ static void *alloc_single_from_partial(struct kmem_cache *s,
slab->inuse++;
if (!alloc_debug_processing(s, slab, object, orig_size)) {
remove_partial(n, slab);
if (folio_test_slab(slab_folio(slab)))
remove_partial(n, slab);
return NULL;
}
@ -3956,6 +3953,28 @@ redo:
object = c->freelist;
slab = c->slab;
#ifdef CONFIG_NUMA
if (static_branch_unlikely(&strict_numa) &&
node == NUMA_NO_NODE) {
struct mempolicy *mpol = current->mempolicy;
if (mpol) {
/*
* Special BIND rule support. If existing slab
* is in permitted set then do not redirect
* to a particular node.
* Otherwise we apply the memory policy to get
* the node we need to allocate on.
*/
if (mpol->mode != MPOL_BIND || !slab ||
!node_isset(slab_nid(slab), mpol->nodes))
node = mempolicy_slab_node();
}
}
#endif
if (!USE_LOCKLESS_FAST_PATH() ||
unlikely(!object || !slab || !node_match(slab, node))) {
object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
@ -4728,6 +4747,126 @@ void kfree(const void *object)
}
EXPORT_SYMBOL(kfree);
static __always_inline __realloc_size(2) void *
__do_krealloc(const void *p, size_t new_size, gfp_t flags)
{
void *ret;
size_t ks = 0;
int orig_size = 0;
struct kmem_cache *s = NULL;
if (unlikely(ZERO_OR_NULL_PTR(p)))
goto alloc_new;
/* Check for double-free. */
if (!kasan_check_byte(p))
return NULL;
if (is_kfence_address(p)) {
ks = orig_size = kfence_ksize(p);
} else {
struct folio *folio;
folio = virt_to_folio(p);
if (unlikely(!folio_test_slab(folio))) {
/* Big kmalloc object */
WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE);
WARN_ON(p != folio_address(folio));
ks = folio_size(folio);
} else {
s = folio_slab(folio)->slab_cache;
orig_size = get_orig_size(s, (void *)p);
ks = s->object_size;
}
}
/* If the old object doesn't fit, allocate a bigger one */
if (new_size > ks)
goto alloc_new;
/* Zero out spare memory. */
if (want_init_on_alloc(flags)) {
kasan_disable_current();
if (orig_size && orig_size < new_size)
memset(kasan_reset_tag(p) + orig_size, 0, new_size - orig_size);
else
memset(kasan_reset_tag(p) + new_size, 0, ks - new_size);
kasan_enable_current();
}
/* Setup kmalloc redzone when needed */
if (s && slub_debug_orig_size(s)) {
set_orig_size(s, (void *)p, new_size);
if (s->flags & SLAB_RED_ZONE && new_size < ks)
memset_no_sanitize_memory(kasan_reset_tag(p) + new_size,
SLUB_RED_ACTIVE, ks - new_size);
}
p = kasan_krealloc(p, new_size, flags);
return (void *)p;
alloc_new:
ret = kmalloc_node_track_caller_noprof(new_size, flags, NUMA_NO_NODE, _RET_IP_);
if (ret && p) {
/* Disable KASAN checks as the object's redzone is accessed. */
kasan_disable_current();
memcpy(ret, kasan_reset_tag(p), orig_size ?: 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.
*
* 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.
*
* If __GFP_ZERO logic is requested, callers must ensure that, starting with the
* initial memory allocation, every subsequent call to this API for the same
* memory allocation is flagged with __GFP_ZERO. Otherwise, it is possible that
* __GFP_ZERO is not fully honored by this API.
*
* When slub_debug_orig_size() is off, krealloc() only knows about the bucket
* size of an allocation (but not the exact size it was allocated with) and
* hence implements the following semantics for shrinking and growing buffers
* with __GFP_ZERO.
*
* new bucket
* 0 size size
* |--------|----------------|
* | keep | zero |
*
* Otherwise, the original allocation size 'orig_size' could be used to
* precisely clear the requested size, and the new size will also be stored
* as the new 'orig_size'.
*
* In any case, the contents of the object pointed to are preserved up to the
* lesser of the new and old sizes.
*
* Return: pointer to the allocated memory or %NULL in case of error
*/
void *krealloc_noprof(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_noprof);
struct detached_freelist {
struct slab *slab;
void *tail;
@ -5602,6 +5741,23 @@ static int __init setup_slub_min_objects(char *str)
__setup("slab_min_objects=", setup_slub_min_objects);
__setup_param("slub_min_objects=", slub_min_objects, setup_slub_min_objects, 0);
#ifdef CONFIG_NUMA
static int __init setup_slab_strict_numa(char *str)
{
if (nr_node_ids > 1) {
static_branch_enable(&strict_numa);
pr_info("SLUB: Strict NUMA enabled.\n");
} else {
pr_warn("slab_strict_numa parameter set on non NUMA system.\n");
}
return 1;
}
__setup("slab_strict_numa", setup_slab_strict_numa);
#endif
#ifdef CONFIG_HARDENED_USERCOPY
/*
* Rejects incorrectly sized objects and objects that are to be copied
@ -5960,7 +6116,8 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
s = find_mergeable(size, align, flags, name, ctor);
if (s) {
if (sysfs_slab_alias(s, name))
return NULL;
pr_err("SLUB: Unable to add cache alias %s to sysfs\n",
name);
s->refcount++;
@ -6042,16 +6199,19 @@ int do_kmem_cache_create(struct kmem_cache *s, const char *name,
if (!alloc_kmem_cache_cpus(s))
goto out;
/* Mutex is not taken during early boot */
if (slab_state <= UP) {
err = 0;
goto out;
}
err = 0;
err = sysfs_slab_add(s);
if (err)
/* Mutex is not taken during early boot */
if (slab_state <= UP)
goto out;
/*
* Failing to create sysfs files is not critical to SLUB functionality.
* If it fails, proceed with cache creation without these files.
*/
if (sysfs_slab_add(s))
pr_err("SLUB: Unable to add cache %s to sysfs\n", s->name);
if (s->flags & SLAB_STORE_USER)
debugfs_slab_add(s);
@ -7120,7 +7280,8 @@ out_del_kobj:
void sysfs_slab_unlink(struct kmem_cache *s)
{
kobject_del(&s->kobj);
if (s->kobj.state_in_sysfs)
kobject_del(&s->kobj);
}
void sysfs_slab_release(struct kmem_cache *s)
@ -7149,6 +7310,11 @@ static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
* If we have a leftover link then remove it.
*/
sysfs_remove_link(&slab_kset->kobj, name);
/*
* The original cache may have failed to generate sysfs file.
* In that case, sysfs_create_link() returns -ENOENT and
* symbolic link creation is skipped.
*/
return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
}