diff options
Diffstat (limited to 'mm/slab_common.c')
| -rw-r--r-- | mm/slab_common.c | 1456 |
1 files changed, 1456 insertions, 0 deletions
diff --git a/mm/slab_common.c b/mm/slab_common.c new file mode 100644 index 000000000..4736c0e60 --- /dev/null +++ b/mm/slab_common.c @@ -0,0 +1,1456 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Slab allocator functions that are independent of the allocator strategy + * + * (C) 2012 Christoph Lameter <cl@linux.com> + */ +#include <linux/slab.h> + +#include <linux/mm.h> +#include <linux/poison.h> +#include <linux/interrupt.h> +#include <linux/memory.h> +#include <linux/cache.h> +#include <linux/compiler.h> +#include <linux/kfence.h> +#include <linux/module.h> +#include <linux/cpu.h> +#include <linux/uaccess.h> +#include <linux/seq_file.h> +#include <linux/proc_fs.h> +#include <linux/debugfs.h> +#include <linux/kasan.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm/page.h> +#include <linux/memcontrol.h> +#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; + +static LIST_HEAD(slab_caches_to_rcu_destroy); +static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work); +static DECLARE_WORK(slab_caches_to_rcu_destroy_work, + slab_caches_to_rcu_destroy_workfn); + +/* + * Set of flags that will prevent slab merging + */ +#define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ + SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ + SLAB_FAILSLAB | kasan_never_merge()) + +#define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ + SLAB_CACHE_DMA32 | SLAB_ACCOUNT) + +/* + * Merge control. If this is set then no merging of slab caches will occur. + */ +static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT); + +static int __init setup_slab_nomerge(char *str) +{ + slab_nomerge = true; + return 1; +} + +static int __init setup_slab_merge(char *str) +{ + slab_nomerge = false; + return 1; +} + +#ifdef CONFIG_SLUB +__setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); +__setup_param("slub_merge", slub_merge, setup_slab_merge, 0); +#endif + +__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 int kmem_cache_sanity_check(const char *name, unsigned int size) +{ + if (!name || in_interrupt() || size > KMALLOC_MAX_SIZE) { + pr_err("kmem_cache_create(%s) integrity check failed\n", name); + return -EINVAL; + } + + WARN_ON(strchr(name, ' ')); /* It confuses parsers */ + return 0; +} +#else +static inline int kmem_cache_sanity_check(const char *name, unsigned int size) +{ + return 0; +} +#endif + +/* + * 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; + + if (s->usersize) + return 1; + + /* + * We may have set a slab to be unmergeable during bootstrap. + */ + if (s->refcount < 0) + return 1; + + return 0; +} + +struct kmem_cache *find_mergeable(unsigned int size, unsigned int align, + slab_flags_t flags, const char *name, void (*ctor)(void *)) +{ + struct kmem_cache *s; + + if (slab_nomerge) + return NULL; + + if (ctor) + return NULL; + + size = ALIGN(size, sizeof(void *)); + align = calculate_alignment(flags, align, size); + size = ALIGN(size, align); + flags = kmem_cache_flags(size, flags, name); + + if (flags & SLAB_NEVER_MERGE) + return NULL; + + list_for_each_entry_reverse(s, &slab_caches, list) { + if (slab_unmergeable(s)) + continue; + + if (size > s->size) + continue; + + if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) + continue; + /* + * Check if alignment is compatible. + * Courtesy of Adrian Drzewiecki + */ + if ((s->size & ~(align - 1)) != s->size) + continue; + + if (s->size - size >= sizeof(void *)) + continue; + + if (IS_ENABLED(CONFIG_SLAB) && align && + (align > s->align || s->align % align)) + continue; + + return s; + } + return NULL; +} + +static struct kmem_cache *create_cache(const char *name, + unsigned int object_size, unsigned int align, + slab_flags_t flags, unsigned int useroffset, + unsigned int usersize, void (*ctor)(void *), + struct kmem_cache *root_cache) +{ + struct kmem_cache *s; + int err; + + if (WARN_ON(useroffset + usersize > object_size)) + useroffset = usersize = 0; + + err = -ENOMEM; + s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); + if (!s) + goto out; + + s->name = name; + s->size = s->object_size = object_size; + s->align = align; + s->ctor = ctor; + s->useroffset = useroffset; + s->usersize = usersize; + + err = __kmem_cache_create(s, flags); + if (err) + goto out_free_cache; + + s->refcount = 1; + list_add(&s->list, &slab_caches); +out: + if (err) + return ERR_PTR(err); + return s; + +out_free_cache: + kmem_cache_free(kmem_cache, s); + goto out; +} + +/** + * kmem_cache_create_usercopy - Create a cache with a region suitable + * for copying to userspace + * @name: A string which is used in /proc/slabinfo to identify this cache. + * @size: The size of objects to be created in this cache. + * @align: The required alignment for the objects. + * @flags: SLAB flags + * @useroffset: Usercopy region offset + * @usersize: Usercopy region size + * @ctor: A constructor for the objects. + * + * Cannot be called within a interrupt, but can be interrupted. + * The @ctor is run when new pages are allocated by the cache. + * + * The flags are + * + * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) + * to catch references to uninitialised memory. + * + * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check + * for buffer overruns. + * + * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware + * cacheline. This can be beneficial if you're counting cycles as closely + * as davem. + * + * Return: a pointer to the cache on success, NULL on failure. + */ +struct kmem_cache * +kmem_cache_create_usercopy(const char *name, + unsigned int size, unsigned int align, + slab_flags_t flags, + unsigned int useroffset, unsigned int usersize, + void (*ctor)(void *)) +{ + struct kmem_cache *s = NULL; + const char *cache_name; + int err; + +#ifdef CONFIG_SLUB_DEBUG + /* + * If no slub_debug was enabled globally, the static key is not yet + * enabled by setup_slub_debug(). Enable it if the cache is being + * created with any of the debugging flags passed explicitly. + * 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, size); + if (err) { + goto out_unlock; + } + + /* Refuse requests with allocator specific flags */ + if (flags & ~SLAB_FLAGS_PERMITTED) { + err = -EINVAL; + goto out_unlock; + } + + /* + * Some allocators will constraint the set of valid flags to a subset + * of all flags. We expect them to define CACHE_CREATE_MASK in this + * case, and we'll just provide them with a sanitized version of the + * passed flags. + */ + flags &= CACHE_CREATE_MASK; + + /* Fail closed on bad usersize of useroffset values. */ + if (WARN_ON(!usersize && useroffset) || + WARN_ON(size < usersize || size - usersize < useroffset)) + usersize = useroffset = 0; + + if (!usersize) + s = __kmem_cache_alias(name, size, align, flags, ctor); + if (s) + goto out_unlock; + + cache_name = kstrdup_const(name, GFP_KERNEL); + if (!cache_name) { + err = -ENOMEM; + goto out_unlock; + } + + s = create_cache(cache_name, size, + calculate_alignment(flags, align, size), + flags, useroffset, usersize, ctor, NULL); + if (IS_ERR(s)) { + err = PTR_ERR(s); + kfree_const(cache_name); + } + +out_unlock: + mutex_unlock(&slab_mutex); + + 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_usercopy); + +/** + * kmem_cache_create - Create a cache. + * @name: A string which is used in /proc/slabinfo to identify this cache. + * @size: The size of objects to be created in this cache. + * @align: The required alignment for the objects. + * @flags: SLAB flags + * @ctor: A constructor for the objects. + * + * Cannot be called within a interrupt, but can be interrupted. + * The @ctor is run when new pages are allocated by the cache. + * + * The flags are + * + * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) + * to catch references to uninitialised memory. + * + * %SLAB_RED_ZONE - Insert `Red` zones around the allocated memory to check + * for buffer overruns. + * + * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware + * cacheline. This can be beneficial if you're counting cycles as closely + * as davem. + * + * Return: a pointer to the cache on success, NULL on failure. + */ +struct kmem_cache * +kmem_cache_create(const char *name, unsigned int size, unsigned int align, + slab_flags_t flags, void (*ctor)(void *)) +{ + return kmem_cache_create_usercopy(name, size, align, flags, 0, 0, + ctor); +} +EXPORT_SYMBOL(kmem_cache_create); + +#ifdef SLAB_SUPPORTS_SYSFS +/* + * 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. + * + * Note that there will be a slight delay in the deletion of sysfs files + * if kmem_cache_release() is called indrectly from a work function. + */ +static void kmem_cache_release(struct kmem_cache *s) +{ + sysfs_slab_unlink(s); + sysfs_slab_release(s); +} +#else +static void kmem_cache_release(struct kmem_cache *s) +{ + slab_kmem_cache_release(s); +} +#endif + +static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) +{ + LIST_HEAD(to_destroy); + struct kmem_cache *s, *s2; + + /* + * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the + * @slab_caches_to_rcu_destroy list. The slab pages are freed + * through RCU and the associated kmem_cache are dereferenced + * while freeing the pages, so the kmem_caches should be freed only + * after the pending RCU operations are finished. As rcu_barrier() + * is a pretty slow operation, we batch all pending destructions + * asynchronously. + */ + mutex_lock(&slab_mutex); + list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy); + mutex_unlock(&slab_mutex); + + if (list_empty(&to_destroy)) + return; + + rcu_barrier(); + + list_for_each_entry_safe(s, s2, &to_destroy, list) { + debugfs_slab_release(s); + kfence_shutdown_cache(s); + kmem_cache_release(s); + } +} + +static int shutdown_cache(struct kmem_cache *s) +{ + /* free asan quarantined objects */ + kasan_cache_shutdown(s); + + if (__kmem_cache_shutdown(s) != 0) + return -EBUSY; + + list_del(&s->list); + + if (s->flags & SLAB_TYPESAFE_BY_RCU) { + list_add_tail(&s->list, &slab_caches_to_rcu_destroy); + schedule_work(&slab_caches_to_rcu_destroy_work); + } else { + kfence_shutdown_cache(s); + debugfs_slab_release(s); + } + + return 0; +} + +void slab_kmem_cache_release(struct kmem_cache *s) +{ + __kmem_cache_release(s); + kfree_const(s->name); + kmem_cache_free(kmem_cache, s); +} + +void kmem_cache_destroy(struct kmem_cache *s) +{ + int err = -EBUSY; + 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; + + s->refcount--; + if (s->refcount) + goto out_unlock; + + err = shutdown_cache(s); + WARN(err, "%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 (!err && !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); |