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![Vlastimil Babka](/assets/img/avatar_default.png)
Akira reports: > "make htmldocs" reports duplicate C declaration of ksize() as follows: > /linux/Documentation/core-api/mm-api:43: ./mm/slab_common.c:1428: WARNING: Duplicate C declaration, also defined at core-api/mm-api:212. > Declaration is '.. c:function:: size_t ksize (const void *objp)'. > This is due to the kernel-doc comment for ksize() declaration added in > include/linux/slab.h by commit05a940656e
("slab: Introduce > kmalloc_size_roundup()"). There is an older kernel-doc comment for ksize() definition in mm/slab_common.c, which is not only duplicated, but also contradicts the new one - the additional storage discovered by ksize() should not be used by callers anymore. Delete the old kernel-doc. Reported-by: Akira Yokosawa <akiyks@gmail.com> Link: https://lore.kernel.org/all/d33440f6-40cf-9747-3340-e54ffaf7afb8@gmail.com/ Fixes:05a940656e
("slab: Introduce kmalloc_size_roundup()") Cc: Kees Cook <keescook@chromium.org> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
1456 lines
37 KiB
C
1456 lines
37 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Slab allocator functions that are independent of the allocator strategy
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*
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* (C) 2012 Christoph Lameter <cl@linux.com>
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*/
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#include <linux/slab.h>
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#include <linux/mm.h>
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#include <linux/poison.h>
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#include <linux/interrupt.h>
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#include <linux/memory.h>
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#include <linux/cache.h>
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#include <linux/compiler.h>
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#include <linux/kfence.h>
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#include <linux/module.h>
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#include <linux/cpu.h>
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#include <linux/uaccess.h>
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#include <linux/seq_file.h>
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#include <linux/proc_fs.h>
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#include <linux/debugfs.h>
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#include <linux/kasan.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include <asm/page.h>
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#include <linux/memcontrol.h>
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#include <linux/stackdepot.h>
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#include "internal.h"
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#include "slab.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/kmem.h>
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enum slab_state slab_state;
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LIST_HEAD(slab_caches);
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DEFINE_MUTEX(slab_mutex);
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struct kmem_cache *kmem_cache;
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static LIST_HEAD(slab_caches_to_rcu_destroy);
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static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
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static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
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slab_caches_to_rcu_destroy_workfn);
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/*
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* Set of flags that will prevent slab merging
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*/
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#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
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SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \
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SLAB_FAILSLAB | kasan_never_merge())
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#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \
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SLAB_CACHE_DMA32 | SLAB_ACCOUNT)
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/*
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* Merge control. If this is set then no merging of slab caches will occur.
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*/
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static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT);
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static int __init setup_slab_nomerge(char *str)
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{
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slab_nomerge = true;
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return 1;
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}
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static int __init setup_slab_merge(char *str)
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{
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slab_nomerge = false;
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return 1;
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}
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#ifdef CONFIG_SLUB
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__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0);
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__setup_param("slub_merge", slub_merge, setup_slab_merge, 0);
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#endif
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__setup("slab_nomerge", setup_slab_nomerge);
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__setup("slab_merge", setup_slab_merge);
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/*
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* Determine the size of a slab object
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*/
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unsigned int kmem_cache_size(struct kmem_cache *s)
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{
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return s->object_size;
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}
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EXPORT_SYMBOL(kmem_cache_size);
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#ifdef CONFIG_DEBUG_VM
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static int kmem_cache_sanity_check(const char *name, unsigned int size)
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{
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if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) {
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pr_err("kmem_cache_create(%s) integrity check failed\n", name);
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return -EINVAL;
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}
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WARN_ON(strchr(name, ' ')); /* It confuses parsers */
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return 0;
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}
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#else
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static inline int kmem_cache_sanity_check(const char *name, unsigned int size)
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{
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return 0;
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}
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#endif
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/*
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* Figure out what the alignment of the objects will be given a set of
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* flags, a user specified alignment and the size of the objects.
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*/
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static unsigned int calculate_alignment(slab_flags_t flags,
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unsigned int align, unsigned int size)
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{
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/*
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* If the user wants hardware cache aligned objects then follow that
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* suggestion if the object is sufficiently large.
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*
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* The hardware cache alignment cannot override the specified
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* alignment though. If that is greater then use it.
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*/
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if (flags & SLAB_HWCACHE_ALIGN) {
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unsigned int ralign;
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ralign = cache_line_size();
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while (size <= ralign / 2)
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ralign /= 2;
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align = max(align, ralign);
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}
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align = max(align, arch_slab_minalign());
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return ALIGN(align, sizeof(void *));
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}
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/*
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* Find a mergeable slab cache
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*/
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int slab_unmergeable(struct kmem_cache *s)
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{
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if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE))
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return 1;
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if (s->ctor)
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return 1;
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if (s->usersize)
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return 1;
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/*
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* We may have set a slab to be unmergeable during bootstrap.
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*/
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if (s->refcount < 0)
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return 1;
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return 0;
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}
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struct kmem_cache *find_mergeable(unsigned int size, unsigned int align,
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slab_flags_t flags, const char *name, void (*ctor)(void *))
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{
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struct kmem_cache *s;
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if (slab_nomerge)
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return NULL;
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if (ctor)
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return NULL;
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size = ALIGN(size, sizeof(void *));
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align = calculate_alignment(flags, align, size);
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size = ALIGN(size, align);
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flags = kmem_cache_flags(size, flags, name);
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if (flags & SLAB_NEVER_MERGE)
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return NULL;
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list_for_each_entry_reverse(s, &slab_caches, list) {
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if (slab_unmergeable(s))
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continue;
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if (size > s->size)
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continue;
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if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME))
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continue;
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/*
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* Check if alignment is compatible.
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* Courtesy of Adrian Drzewiecki
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*/
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if ((s->size & ~(align - 1)) != s->size)
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continue;
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if (s->size - size >= sizeof(void *))
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continue;
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if (IS_ENABLED(CONFIG_SLAB) && align &&
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(align > s->align || s->align % align))
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continue;
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return s;
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}
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return NULL;
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}
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static struct kmem_cache *create_cache(const char *name,
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unsigned int object_size, unsigned int align,
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slab_flags_t flags, unsigned int useroffset,
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unsigned int usersize, void (*ctor)(void *),
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struct kmem_cache *root_cache)
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{
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struct kmem_cache *s;
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int err;
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if (WARN_ON(useroffset + usersize > object_size))
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useroffset = usersize = 0;
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err = -ENOMEM;
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s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
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if (!s)
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goto out;
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s->name = name;
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s->size = s->object_size = object_size;
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s->align = align;
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s->ctor = ctor;
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s->useroffset = useroffset;
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s->usersize = usersize;
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err = __kmem_cache_create(s, flags);
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if (err)
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goto out_free_cache;
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s->refcount = 1;
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list_add(&s->list, &slab_caches);
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out:
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if (err)
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return ERR_PTR(err);
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return s;
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out_free_cache:
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kmem_cache_free(kmem_cache, s);
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goto out;
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}
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/**
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* kmem_cache_create_usercopy - Create a cache with a region suitable
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* for copying to userspace
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* @name: A string which is used in /proc/slabinfo to identify this cache.
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* @size: The size of objects to be created in this cache.
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* @align: The required alignment for the objects.
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* @flags: SLAB flags
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* @useroffset: Usercopy region offset
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* @usersize: Usercopy region size
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* @ctor: A constructor for the objects.
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*
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* Cannot be called within a interrupt, but can be interrupted.
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* The @ctor is run when new pages are allocated by the cache.
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*
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* The flags are
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*
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* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
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* to catch references to uninitialised memory.
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*
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* %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
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* for buffer overruns.
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*
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* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
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* cacheline. This can be beneficial if you're counting cycles as closely
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* as davem.
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*
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* Return: a pointer to the cache on success, NULL on failure.
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*/
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struct kmem_cache *
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kmem_cache_create_usercopy(const char *name,
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unsigned int size, unsigned int align,
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slab_flags_t flags,
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unsigned int useroffset, unsigned int usersize,
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void (*ctor)(void *))
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{
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struct kmem_cache *s = NULL;
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const char *cache_name;
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int err;
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#ifdef CONFIG_SLUB_DEBUG
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/*
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* If no slub_debug was enabled globally, the static key is not yet
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* enabled by setup_slub_debug(). Enable it if the cache is being
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* created with any of the debugging flags passed explicitly.
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* It's also possible that this is the first cache created with
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* SLAB_STORE_USER and we should init stack_depot for it.
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*/
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if (flags & SLAB_DEBUG_FLAGS)
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static_branch_enable(&slub_debug_enabled);
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if (flags & SLAB_STORE_USER)
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stack_depot_init();
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#endif
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mutex_lock(&slab_mutex);
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err = kmem_cache_sanity_check(name, size);
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if (err) {
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goto out_unlock;
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}
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/* Refuse requests with allocator specific flags */
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if (flags & ~SLAB_FLAGS_PERMITTED) {
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err = -EINVAL;
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goto out_unlock;
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}
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/*
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* Some allocators will constraint the set of valid flags to a subset
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* of all flags. We expect them to define CACHE_CREATE_MASK in this
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* case, and we'll just provide them with a sanitized version of the
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* passed flags.
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*/
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flags &= CACHE_CREATE_MASK;
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/* Fail closed on bad usersize of useroffset values. */
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if (WARN_ON(!usersize && useroffset) ||
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WARN_ON(size < usersize || size - usersize < useroffset))
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usersize = useroffset = 0;
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if (!usersize)
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s = __kmem_cache_alias(name, size, align, flags, ctor);
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if (s)
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goto out_unlock;
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cache_name = kstrdup_const(name, GFP_KERNEL);
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if (!cache_name) {
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err = -ENOMEM;
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goto out_unlock;
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}
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s = create_cache(cache_name, size,
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calculate_alignment(flags, align, size),
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flags, useroffset, usersize, ctor, NULL);
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if (IS_ERR(s)) {
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err = PTR_ERR(s);
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kfree_const(cache_name);
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}
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out_unlock:
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mutex_unlock(&slab_mutex);
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if (err) {
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if (flags & SLAB_PANIC)
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panic("%s: Failed to create slab '%s'. Error %d\n",
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__func__, name, err);
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else {
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pr_warn("%s(%s) failed with error %d\n",
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__func__, name, err);
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dump_stack();
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}
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return NULL;
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}
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return s;
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}
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EXPORT_SYMBOL(kmem_cache_create_usercopy);
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/**
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* kmem_cache_create - Create a cache.
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* @name: A string which is used in /proc/slabinfo to identify this cache.
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* @size: The size of objects to be created in this cache.
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* @align: The required alignment for the objects.
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* @flags: SLAB flags
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* @ctor: A constructor for the objects.
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*
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* Cannot be called within a interrupt, but can be interrupted.
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* The @ctor is run when new pages are allocated by the cache.
|
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*
|
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* The flags are
|
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*
|
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* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
|
|
* to catch references to uninitialised memory.
|
|
*
|
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* %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check
|
|
* for buffer overruns.
|
|
*
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* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
|
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* cacheline. This can be beneficial if you're counting cycles as closely
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* as davem.
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*
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* Return: a pointer to the cache on success, NULL on failure.
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*/
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struct kmem_cache *
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kmem_cache_create(const char *name, unsigned int size, unsigned int align,
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slab_flags_t flags, void (*ctor)(void *))
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{
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return kmem_cache_create_usercopy(name, size, align, flags, 0, 0,
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ctor);
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}
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EXPORT_SYMBOL(kmem_cache_create);
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|
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#ifdef SLAB_SUPPORTS_SYSFS
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/*
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* For a given kmem_cache, kmem_cache_destroy() should only be called
|
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* once or there will be a use-after-free problem. The actual deletion
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* and release of the kobject does not need slab_mutex or cpu_hotplug_lock
|
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* protection. So they are now done without holding those locks.
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*
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* Note that there will be a slight delay in the deletion of sysfs files
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* if kmem_cache_release() is called indrectly from a work function.
|
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*/
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static void kmem_cache_release(struct kmem_cache *s)
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{
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sysfs_slab_unlink(s);
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sysfs_slab_release(s);
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}
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#else
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static void kmem_cache_release(struct kmem_cache *s)
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{
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slab_kmem_cache_release(s);
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}
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#endif
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|
|
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static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work)
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{
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LIST_HEAD(to_destroy);
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struct kmem_cache *s, *s2;
|
|
|
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/*
|
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* On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the
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* @slab_caches_to_rcu_destroy list. The slab pages are freed
|
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* through RCU and the associated kmem_cache are dereferenced
|
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* while freeing the pages, so the kmem_caches should be freed only
|
|
* after the pending RCU operations are finished. As rcu_barrier()
|
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* is a pretty slow operation, we batch all pending destructions
|
|
* asynchronously.
|
|
*/
|
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mutex_lock(&slab_mutex);
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|
list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy);
|
|
mutex_unlock(&slab_mutex);
|
|
|
|
if (list_empty(&to_destroy))
|
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return;
|
|
|
|
rcu_barrier();
|
|
|
|
list_for_each_entry_safe(s, s2, &to_destroy, list) {
|
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debugfs_slab_release(s);
|
|
kfence_shutdown_cache(s);
|
|
kmem_cache_release(s);
|
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}
|
|
}
|
|
|
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static int shutdown_cache(struct kmem_cache *s)
|
|
{
|
|
/* free asan quarantined objects */
|
|
kasan_cache_shutdown(s);
|
|
|
|
if (__kmem_cache_shutdown(s) != 0)
|
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return -EBUSY;
|
|
|
|
list_del(&s->list);
|
|
|
|
if (s->flags & SLAB_TYPESAFE_BY_RCU) {
|
|
list_add_tail(&s->list, &slab_caches_to_rcu_destroy);
|
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schedule_work(&slab_caches_to_rcu_destroy_work);
|
|
} else {
|
|
kfence_shutdown_cache(s);
|
|
debugfs_slab_release(s);
|
|
}
|
|
|
|
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 refcnt;
|
|
bool rcu_set;
|
|
|
|
if (unlikely(!s) || !kasan_check_byte(s))
|
|
return;
|
|
|
|
cpus_read_lock();
|
|
mutex_lock(&slab_mutex);
|
|
|
|
rcu_set = s->flags & SLAB_TYPESAFE_BY_RCU;
|
|
|
|
refcnt = --s->refcount;
|
|
if (refcnt)
|
|
goto out_unlock;
|
|
|
|
WARN(shutdown_cache(s),
|
|
"%s %s: Slab cache still has objects when called from %pS",
|
|
__func__, s->name, (void *)_RET_IP_);
|
|
out_unlock:
|
|
mutex_unlock(&slab_mutex);
|
|
cpus_read_unlock();
|
|
if (!refcnt && !rcu_set)
|
|
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
|
|
/**
|
|
* kmem_valid_obj - does the pointer reference a valid slab object?
|
|
* @object: pointer to query.
|
|
*
|
|
* 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_valid_obj(void *object)
|
|
{
|
|
struct folio *folio;
|
|
|
|
/* Some arches consider ZERO_SIZE_PTR to be a valid address. */
|
|
if (object < (void *)PAGE_SIZE || !virt_addr_valid(object))
|
|
return false;
|
|
folio = virt_to_folio(object);
|
|
return folio_test_slab(folio);
|
|
}
|
|
EXPORT_SYMBOL_GPL(kmem_valid_obj);
|
|
|
|
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.
|
|
*
|
|
* This function will splat if passed a pointer to a non-slab object.
|
|
* If you are not sure what type of object you have, you should instead
|
|
* use mem_dump_obj().
|
|
*/
|
|
void 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 = { };
|
|
|
|
if (WARN_ON_ONCE(!virt_addr_valid(object)))
|
|
return;
|
|
slab = virt_to_slab(object);
|
|
if (WARN_ON_ONCE(!slab)) {
|
|
pr_cont(" non-slab memory.\n");
|
|
return;
|
|
}
|
|
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->usersize)
|
|
pr_cont(" size %u", kp.kp_slab_cache->usersize);
|
|
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]);
|
|
}
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(kmem_dump_obj);
|
|
#endif
|
|
|
|
#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 | SLAB_KMALLOC, 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;
|
|
|
|
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);
|
|
}
|
|
|
|
return kmalloc_caches[kmalloc_type(flags)][index];
|
|
}
|
|
|
|
size_t kmalloc_size_roundup(size_t size)
|
|
{
|
|
struct kmem_cache *c;
|
|
|
|
/* Short-circuit the 0 size case. */
|
|
if (unlikely(size == 0))
|
|
return 0;
|
|
/* Short-circuit saturated "too-large" case. */
|
|
if (unlikely(size == SIZE_MAX))
|
|
return SIZE_MAX;
|
|
/* Above the smaller buckets, size is a multiple of page size. */
|
|
if (size > KMALLOC_MAX_CACHE_SIZE)
|
|
return PAGE_SIZE << get_order(size);
|
|
|
|
/* The flags don't matter since size_index is common to all. */
|
|
c = kmalloc_slab(size, GFP_KERNEL);
|
|
return c ? c->object_size : 0;
|
|
}
|
|
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_KMEM
|
|
#define KMALLOC_CGROUP_NAME(sz) .name[KMALLOC_CGROUP] = "kmalloc-cg-" #sz,
|
|
#else
|
|
#define KMALLOC_CGROUP_NAME(sz)
|
|
#endif
|
|
|
|
#define INIT_KMALLOC_INFO(__size, __short_size) \
|
|
{ \
|
|
.name[KMALLOC_NORMAL] = "kmalloc-" #__short_size, \
|
|
.name[KMALLOC_RECLAIM] = "kmalloc-rcl-" #__short_size, \
|
|
KMALLOC_CGROUP_NAME(__short_size) \
|
|
KMALLOC_DMA_NAME(__short_size) \
|
|
.size = __size, \
|
|
}
|
|
|
|
/*
|
|
* kmalloc_info[] is to make slub_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(size_index))
|
|
break;
|
|
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)
|
|
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;
|
|
} else if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (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;
|
|
}
|
|
|
|
kmalloc_caches[type][idx] = create_kmalloc_cache(
|
|
kmalloc_info[idx].name[type],
|
|
kmalloc_info[idx].size, flags, 0,
|
|
kmalloc_info[idx].size);
|
|
|
|
/*
|
|
* If CONFIG_MEMCG_KMEM is enabled, disable cache merging for
|
|
* KMALLOC_NORMAL caches.
|
|
*/
|
|
if (IS_ENABLED(CONFIG_MEMCG_KMEM) && (type == KMALLOC_NORMAL))
|
|
kmalloc_caches[type][idx]->refcount = -1;
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
|
|
/*
|
|
* Including KMALLOC_CGROUP if CONFIG_MEMCG_KMEM defined
|
|
*/
|
|
for (type = KMALLOC_NORMAL; type < NR_KMALLOC_TYPES; 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;
|
|
}
|
|
|
|
void free_large_kmalloc(struct folio *folio, void *object)
|
|
{
|
|
unsigned int order = folio_order(folio);
|
|
|
|
if (WARN_ON_ONCE(order == 0))
|
|
pr_warn_once("object pointer: 0x%p\n", object);
|
|
|
|
kmemleak_free(object);
|
|
kasan_kfree_large(object);
|
|
kmsan_kfree_large(object);
|
|
|
|
mod_lruvec_page_state(folio_page(folio, 0), NR_SLAB_UNRECLAIMABLE_B,
|
|
-(PAGE_SIZE << order));
|
|
__free_pages(folio_page(folio, 0), order);
|
|
}
|
|
|
|
static void *__kmalloc_large_node(size_t size, gfp_t flags, int node);
|
|
static __always_inline
|
|
void *__do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
|
|
{
|
|
struct kmem_cache *s;
|
|
void *ret;
|
|
|
|
if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
|
|
ret = __kmalloc_large_node(size, flags, node);
|
|
trace_kmalloc(caller, ret, size,
|
|
PAGE_SIZE << get_order(size), flags, node);
|
|
return ret;
|
|
}
|
|
|
|
s = kmalloc_slab(size, flags);
|
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(s)))
|
|
return s;
|
|
|
|
ret = __kmem_cache_alloc_node(s, flags, node, size, caller);
|
|
ret = kasan_kmalloc(s, ret, size, flags);
|
|
trace_kmalloc(caller, ret, size, s->size, flags, node);
|
|
return ret;
|
|
}
|
|
|
|
void *__kmalloc_node(size_t size, gfp_t flags, int node)
|
|
{
|
|
return __do_kmalloc_node(size, flags, node, _RET_IP_);
|
|
}
|
|
EXPORT_SYMBOL(__kmalloc_node);
|
|
|
|
void *__kmalloc(size_t size, gfp_t flags)
|
|
{
|
|
return __do_kmalloc_node(size, flags, NUMA_NO_NODE, _RET_IP_);
|
|
}
|
|
EXPORT_SYMBOL(__kmalloc);
|
|
|
|
void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
|
|
int node, unsigned long caller)
|
|
{
|
|
return __do_kmalloc_node(size, flags, node, caller);
|
|
}
|
|
EXPORT_SYMBOL(__kmalloc_node_track_caller);
|
|
|
|
/**
|
|
* kfree - free previously allocated memory
|
|
* @object: pointer returned by kmalloc.
|
|
*
|
|
* If @object is NULL, no operation is performed.
|
|
*
|
|
* Don't free memory not originally allocated by kmalloc()
|
|
* or you will run into trouble.
|
|
*/
|
|
void kfree(const void *object)
|
|
{
|
|
struct folio *folio;
|
|
struct slab *slab;
|
|
struct kmem_cache *s;
|
|
|
|
trace_kfree(_RET_IP_, object);
|
|
|
|
if (unlikely(ZERO_OR_NULL_PTR(object)))
|
|
return;
|
|
|
|
folio = virt_to_folio(object);
|
|
if (unlikely(!folio_test_slab(folio))) {
|
|
free_large_kmalloc(folio, (void *)object);
|
|
return;
|
|
}
|
|
|
|
slab = folio_slab(folio);
|
|
s = slab->slab_cache;
|
|
__kmem_cache_free(s, (void *)object, _RET_IP_);
|
|
}
|
|
EXPORT_SYMBOL(kfree);
|
|
|
|
/**
|
|
* __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);
|
|
}
|
|
|
|
return slab_ksize(folio_slab(folio)->slab_cache);
|
|
}
|
|
|
|
void *kmalloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
|
|
{
|
|
void *ret = __kmem_cache_alloc_node(s, gfpflags, NUMA_NO_NODE,
|
|
size, _RET_IP_);
|
|
|
|
trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, NUMA_NO_NODE);
|
|
|
|
ret = kasan_kmalloc(s, ret, size, gfpflags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmalloc_trace);
|
|
|
|
void *kmalloc_node_trace(struct kmem_cache *s, gfp_t gfpflags,
|
|
int node, size_t size)
|
|
{
|
|
void *ret = __kmem_cache_alloc_node(s, gfpflags, node, size, _RET_IP_);
|
|
|
|
trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags, node);
|
|
|
|
ret = kasan_kmalloc(s, ret, size, gfpflags);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmalloc_node_trace);
|
|
#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.
|
|
*/
|
|
|
|
static void *__kmalloc_large_node(size_t size, gfp_t flags, int node)
|
|
{
|
|
struct page *page;
|
|
void *ptr = NULL;
|
|
unsigned int order = get_order(size);
|
|
|
|
if (unlikely(flags & GFP_SLAB_BUG_MASK))
|
|
flags = kmalloc_fix_flags(flags);
|
|
|
|
flags |= __GFP_COMP;
|
|
page = alloc_pages_node(node, flags, order);
|
|
if (page) {
|
|
ptr = page_address(page);
|
|
mod_lruvec_page_state(page, NR_SLAB_UNRECLAIMABLE_B,
|
|
PAGE_SIZE << order);
|
|
}
|
|
|
|
ptr = kasan_kmalloc_large(ptr, size, flags);
|
|
/* As ptr might get tagged, call kmemleak hook after KASAN. */
|
|
kmemleak_alloc(ptr, size, 1, flags);
|
|
kmsan_kmalloc_large(ptr, size, flags);
|
|
|
|
return ptr;
|
|
}
|
|
|
|
void *kmalloc_large(size_t size, gfp_t flags)
|
|
{
|
|
void *ret = __kmalloc_large_node(size, flags, NUMA_NO_NODE);
|
|
|
|
trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
|
|
flags, NUMA_NO_NODE);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmalloc_large);
|
|
|
|
void *kmalloc_large_node(size_t size, gfp_t flags, int node)
|
|
{
|
|
void *ret = __kmalloc_large_node(size, flags, node);
|
|
|
|
trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << get_order(size),
|
|
flags, node);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(kmalloc_large_node);
|
|
|
|
#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');
|
|
}
|
|
|
|
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);
|
|
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;
|
|
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_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 __realloc_size(2) 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 (__GFP_ZERO flag is effectively ignored).
|
|
* 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);
|
|
|
|
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(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);
|