diff options
Diffstat (limited to 'mm/slub.c')
-rw-r--r-- | mm/slub.c | 363 |
1 files changed, 194 insertions, 169 deletions
diff --git a/mm/slub.c b/mm/slub.c index 2e1355ac056b..6c91324f9370 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -124,6 +124,14 @@ static inline int kmem_cache_debug(struct kmem_cache *s) #endif } +static inline void *fixup_red_left(struct kmem_cache *s, void *p) +{ + if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) + p += s->red_left_pad; + + return p; +} + static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) { #ifdef CONFIG_SLUB_CPU_PARTIAL @@ -160,10 +168,18 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) */ #define MAX_PARTIAL 10 -#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \ +#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \ SLAB_POISON | SLAB_STORE_USER) /* + * These debug flags cannot use CMPXCHG because there might be consistency + * issues when checking or reading debug information + */ +#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \ + SLAB_TRACE) + + +/* * Debugging flags that require metadata to be stored in the slab. These get * disabled when slub_debug=O is used and a cache's min order increases with * metadata. @@ -224,24 +240,6 @@ static inline void stat(const struct kmem_cache *s, enum stat_item si) * Core slab cache functions *******************************************************************/ -/* Verify that a pointer has an address that is valid within a slab page */ -static inline int check_valid_pointer(struct kmem_cache *s, - struct page *page, const void *object) -{ - void *base; - - if (!object) - return 1; - - base = page_address(page); - if (object < base || object >= base + page->objects * s->size || - (object - base) % s->size) { - return 0; - } - - return 1; -} - static inline void *get_freepointer(struct kmem_cache *s, void *object) { return *(void **)(object + s->offset); @@ -271,12 +269,14 @@ static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) /* Loop over all objects in a slab */ #define for_each_object(__p, __s, __addr, __objects) \ - for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\ - __p += (__s)->size) + for (__p = fixup_red_left(__s, __addr); \ + __p < (__addr) + (__objects) * (__s)->size; \ + __p += (__s)->size) #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \ - for (__p = (__addr), __idx = 1; __idx <= __objects;\ - __p += (__s)->size, __idx++) + for (__p = fixup_red_left(__s, __addr), __idx = 1; \ + __idx <= __objects; \ + __p += (__s)->size, __idx++) /* Determine object index from a given position */ static inline int slab_index(void *p, struct kmem_cache *s, void *addr) @@ -284,30 +284,6 @@ static inline int slab_index(void *p, struct kmem_cache *s, void *addr) return (p - addr) / s->size; } -static inline size_t slab_ksize(const struct kmem_cache *s) -{ -#ifdef CONFIG_SLUB_DEBUG - /* - * Debugging requires use of the padding between object - * and whatever may come after it. - */ - if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) - return s->object_size; - -#endif - /* - * If we have the need to store the freelist pointer - * back there or track user information then we can - * only use the space before that information. - */ - if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER)) - return s->inuse; - /* - * Else we can use all the padding etc for the allocation - */ - return s->size; -} - static inline int order_objects(int order, unsigned long size, int reserved) { return ((PAGE_SIZE << order) - reserved) / size; @@ -458,6 +434,22 @@ static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map) set_bit(slab_index(p, s, addr), map); } +static inline int size_from_object(struct kmem_cache *s) +{ + if (s->flags & SLAB_RED_ZONE) + return s->size - s->red_left_pad; + + return s->size; +} + +static inline void *restore_red_left(struct kmem_cache *s, void *p) +{ + if (s->flags & SLAB_RED_ZONE) + p -= s->red_left_pad; + + return p; +} + /* * Debug settings: */ @@ -491,6 +483,26 @@ static inline void metadata_access_disable(void) /* * Object debugging */ + +/* Verify that a pointer has an address that is valid within a slab page */ +static inline int check_valid_pointer(struct kmem_cache *s, + struct page *page, void *object) +{ + void *base; + + if (!object) + return 1; + + base = page_address(page); + object = restore_red_left(s, object); + if (object < base || object >= base + page->objects * s->size || + (object - base) % s->size) { + return 0; + } + + return 1; +} + static void print_section(char *text, u8 *addr, unsigned int length) { metadata_access_enable(); @@ -630,7 +642,9 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n", p, p - addr, get_freepointer(s, p)); - if (p > addr + 16) + if (s->flags & SLAB_RED_ZONE) + print_section("Redzone ", p - s->red_left_pad, s->red_left_pad); + else if (p > addr + 16) print_section("Bytes b4 ", p - 16, 16); print_section("Object ", p, min_t(unsigned long, s->object_size, @@ -647,9 +661,9 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) if (s->flags & SLAB_STORE_USER) off += 2 * sizeof(struct track); - if (off != s->size) + if (off != size_from_object(s)) /* Beginning of the filler is the free pointer */ - print_section("Padding ", p + off, s->size - off); + print_section("Padding ", p + off, size_from_object(s) - off); dump_stack(); } @@ -679,6 +693,9 @@ static void init_object(struct kmem_cache *s, void *object, u8 val) { u8 *p = object; + if (s->flags & SLAB_RED_ZONE) + memset(p - s->red_left_pad, val, s->red_left_pad); + if (s->flags & __OBJECT_POISON) { memset(p, POISON_FREE, s->object_size - 1); p[s->object_size - 1] = POISON_END; @@ -771,11 +788,11 @@ static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) /* We also have user information there */ off += 2 * sizeof(struct track); - if (s->size == off) + if (size_from_object(s) == off) return 1; return check_bytes_and_report(s, page, p, "Object padding", - p + off, POISON_INUSE, s->size - off); + p + off, POISON_INUSE, size_from_object(s) - off); } /* Check the pad bytes at the end of a slab page */ @@ -820,6 +837,10 @@ static int check_object(struct kmem_cache *s, struct page *page, if (s->flags & SLAB_RED_ZONE) { if (!check_bytes_and_report(s, page, object, "Redzone", + object - s->red_left_pad, val, s->red_left_pad)) + return 0; + + if (!check_bytes_and_report(s, page, object, "Redzone", endobject, val, s->inuse - s->object_size)) return 0; } else { @@ -1031,20 +1052,32 @@ static void setup_object_debug(struct kmem_cache *s, struct page *page, init_tracking(s, object); } -static noinline int alloc_debug_processing(struct kmem_cache *s, +static inline int alloc_consistency_checks(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { if (!check_slab(s, page)) - goto bad; + return 0; if (!check_valid_pointer(s, page, object)) { object_err(s, page, object, "Freelist Pointer check fails"); - goto bad; + return 0; } if (!check_object(s, page, object, SLUB_RED_INACTIVE)) - goto bad; + return 0; + + return 1; +} + +static noinline int alloc_debug_processing(struct kmem_cache *s, + struct page *page, + void *object, unsigned long addr) +{ + if (s->flags & SLAB_CONSISTENCY_CHECKS) { + if (!alloc_consistency_checks(s, page, object, addr)) + goto bad; + } /* Success perform special debug activities for allocs */ if (s->flags & SLAB_STORE_USER) @@ -1067,37 +1100,21 @@ bad: return 0; } -/* Supports checking bulk free of a constructed freelist */ -static noinline struct kmem_cache_node *free_debug_processing( - struct kmem_cache *s, struct page *page, - void *head, void *tail, int bulk_cnt, - unsigned long addr, unsigned long *flags) +static inline int free_consistency_checks(struct kmem_cache *s, + struct page *page, void *object, unsigned long addr) { - struct kmem_cache_node *n = get_node(s, page_to_nid(page)); - void *object = head; - int cnt = 0; - - spin_lock_irqsave(&n->list_lock, *flags); - slab_lock(page); - - if (!check_slab(s, page)) - goto fail; - -next_object: - cnt++; - if (!check_valid_pointer(s, page, object)) { slab_err(s, page, "Invalid object pointer 0x%p", object); - goto fail; + return 0; } if (on_freelist(s, page, object)) { object_err(s, page, object, "Object already free"); - goto fail; + return 0; } if (!check_object(s, page, object, SLUB_RED_ACTIVE)) - goto out; + return 0; if (unlikely(s != page->slab_cache)) { if (!PageSlab(page)) { @@ -1110,7 +1127,37 @@ next_object: } else object_err(s, page, object, "page slab pointer corrupt."); - goto fail; + return 0; + } + return 1; +} + +/* Supports checking bulk free of a constructed freelist */ +static noinline int free_debug_processing( + struct kmem_cache *s, struct page *page, + void *head, void *tail, int bulk_cnt, + unsigned long addr) +{ + struct kmem_cache_node *n = get_node(s, page_to_nid(page)); + void *object = head; + int cnt = 0; + unsigned long uninitialized_var(flags); + int ret = 0; + + spin_lock_irqsave(&n->list_lock, flags); + slab_lock(page); + + if (s->flags & SLAB_CONSISTENCY_CHECKS) { + if (!check_slab(s, page)) + goto out; + } + +next_object: + cnt++; + + if (s->flags & SLAB_CONSISTENCY_CHECKS) { + if (!free_consistency_checks(s, page, object, addr)) + goto out; } if (s->flags & SLAB_STORE_USER) @@ -1124,23 +1171,18 @@ next_object: object = get_freepointer(s, object); goto next_object; } + ret = 1; + out: if (cnt != bulk_cnt) slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n", bulk_cnt, cnt); slab_unlock(page); - /* - * Keep node_lock to preserve integrity - * until the object is actually freed - */ - return n; - -fail: - slab_unlock(page); - spin_unlock_irqrestore(&n->list_lock, *flags); - slab_fix(s, "Object at 0x%p not freed", object); - return NULL; + spin_unlock_irqrestore(&n->list_lock, flags); + if (!ret) + slab_fix(s, "Object at 0x%p not freed", object); + return ret; } static int __init setup_slub_debug(char *str) @@ -1172,7 +1214,7 @@ static int __init setup_slub_debug(char *str) for (; *str && *str != ','; str++) { switch (tolower(*str)) { case 'f': - slub_debug |= SLAB_DEBUG_FREE; + slub_debug |= SLAB_CONSISTENCY_CHECKS; break; case 'z': slub_debug |= SLAB_RED_ZONE; @@ -1231,10 +1273,10 @@ static inline void setup_object_debug(struct kmem_cache *s, static inline int alloc_debug_processing(struct kmem_cache *s, struct page *page, void *object, unsigned long addr) { return 0; } -static inline struct kmem_cache_node *free_debug_processing( +static inline int free_debug_processing( struct kmem_cache *s, struct page *page, void *head, void *tail, int bulk_cnt, - unsigned long addr, unsigned long *flags) { return NULL; } + unsigned long addr) { return 0; } static inline int slab_pad_check(struct kmem_cache *s, struct page *page) { return 1; } @@ -1281,36 +1323,6 @@ static inline void kfree_hook(const void *x) kasan_kfree_large(x); } -static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, - gfp_t flags) -{ - flags &= gfp_allowed_mask; - lockdep_trace_alloc(flags); - might_sleep_if(gfpflags_allow_blocking(flags)); - - if (should_failslab(s->object_size, flags, s->flags)) - return NULL; - - return memcg_kmem_get_cache(s, flags); -} - -static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, - size_t size, void **p) -{ - size_t i; - - flags &= gfp_allowed_mask; - for (i = 0; i < size; i++) { - void *object = p[i]; - - kmemcheck_slab_alloc(s, flags, object, slab_ksize(s)); - kmemleak_alloc_recursive(object, s->object_size, 1, - s->flags, flags); - kasan_slab_alloc(s, object); - } - memcg_kmem_put_cache(s); -} - static inline void slab_free_hook(struct kmem_cache *s, void *x) { kmemleak_free_recursive(x, s->flags); @@ -1470,7 +1482,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) set_freepointer(s, p, NULL); } - page->freelist = start; + page->freelist = fixup_red_left(s, start); page->inuse = page->objects; page->frozen = 1; @@ -1506,7 +1518,7 @@ static void __free_slab(struct kmem_cache *s, struct page *page) int order = compound_order(page); int pages = 1 << order; - if (kmem_cache_debug(s)) { + if (s->flags & SLAB_CONSISTENCY_CHECKS) { void *p; slab_pad_check(s, page); @@ -1592,18 +1604,12 @@ static inline void add_partial(struct kmem_cache_node *n, __add_partial(n, page, tail); } -static inline void -__remove_partial(struct kmem_cache_node *n, struct page *page) -{ - list_del(&page->lru); - n->nr_partial--; -} - static inline void remove_partial(struct kmem_cache_node *n, struct page *page) { lockdep_assert_held(&n->list_lock); - __remove_partial(n, page); + list_del(&page->lru); + n->nr_partial--; } /* @@ -2230,8 +2236,8 @@ slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs)) return; - pr_warn("SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n", - nid, gfpflags); + pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n", + nid, gfpflags, &gfpflags); pr_warn(" cache: %s, object size: %d, buffer size: %d, default order: %d, min order: %d\n", s->name, s->object_size, s->size, oo_order(s->oo), oo_order(s->min)); @@ -2648,8 +2654,7 @@ static void __slab_free(struct kmem_cache *s, struct page *page, stat(s, FREE_SLOWPATH); if (kmem_cache_debug(s) && - !(n = free_debug_processing(s, page, head, tail, cnt, - addr, &flags))) + !free_debug_processing(s, page, head, tail, cnt, addr)) return; do { @@ -2821,6 +2826,7 @@ struct detached_freelist { void *tail; void *freelist; int cnt; + struct kmem_cache *s; }; /* @@ -2835,26 +2841,45 @@ struct detached_freelist { * synchronization primitive. Look ahead in the array is limited due * to performance reasons. */ -static int build_detached_freelist(struct kmem_cache *s, size_t size, - void **p, struct detached_freelist *df) +static inline +int build_detached_freelist(struct kmem_cache *s, size_t size, + void **p, struct detached_freelist *df) { size_t first_skipped_index = 0; int lookahead = 3; void *object; + struct page *page; /* Always re-init detached_freelist */ df->page = NULL; do { object = p[--size]; + /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */ } while (!object && size); if (!object) return 0; + page = virt_to_head_page(object); + if (!s) { + /* Handle kalloc'ed objects */ + if (unlikely(!PageSlab(page))) { + BUG_ON(!PageCompound(page)); + kfree_hook(object); + __free_kmem_pages(page, compound_order(page)); + p[size] = NULL; /* mark object processed */ + return size; + } + /* Derive kmem_cache from object */ + df->s = page->slab_cache; + } else { + df->s = cache_from_obj(s, object); /* Support for memcg */ + } + /* Start new detached freelist */ - set_freepointer(s, object, NULL); - df->page = virt_to_head_page(object); + df->page = page; + set_freepointer(df->s, object, NULL); df->tail = object; df->freelist = object; p[size] = NULL; /* mark object processed */ @@ -2868,7 +2893,7 @@ static int build_detached_freelist(struct kmem_cache *s, size_t size, /* df->page is always set at this point */ if (df->page == virt_to_head_page(object)) { /* Opportunity build freelist */ - set_freepointer(s, object, df->freelist); + set_freepointer(df->s, object, df->freelist); df->freelist = object; df->cnt++; p[size] = NULL; /* mark object processed */ @@ -2887,25 +2912,20 @@ static int build_detached_freelist(struct kmem_cache *s, size_t size, return first_skipped_index; } - /* Note that interrupts must be enabled when calling this function. */ -void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) +void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p) { if (WARN_ON(!size)) return; do { struct detached_freelist df; - struct kmem_cache *s; - - /* Support for memcg */ - s = cache_from_obj(orig_s, p[size - 1]); size = build_detached_freelist(s, size, p, &df); if (unlikely(!df.page)) continue; - slab_free(s, df.page, df.freelist, df.tail, df.cnt, _RET_IP_); + slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_); } while (likely(size)); } EXPORT_SYMBOL(kmem_cache_free_bulk); @@ -3184,6 +3204,12 @@ static void free_kmem_cache_nodes(struct kmem_cache *s) } } +void __kmem_cache_release(struct kmem_cache *s) +{ + free_percpu(s->cpu_slab); + free_kmem_cache_nodes(s); +} + static int init_kmem_cache_nodes(struct kmem_cache *s) { int node; @@ -3285,7 +3311,7 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) */ size += 2 * sizeof(struct track); - if (flags & SLAB_RED_ZONE) + if (flags & SLAB_RED_ZONE) { /* * Add some empty padding so that we can catch * overwrites from earlier objects rather than let @@ -3294,6 +3320,11 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) * of the object. */ size += sizeof(void *); + + s->red_left_pad = sizeof(void *); + s->red_left_pad = ALIGN(s->red_left_pad, s->align); + size += s->red_left_pad; + } #endif /* @@ -3357,7 +3388,7 @@ static int kmem_cache_open(struct kmem_cache *s, unsigned long flags) #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) - if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0) + if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0) /* Enable fast mode */ s->flags |= __CMPXCHG_DOUBLE; #endif @@ -3443,28 +3474,31 @@ static void list_slab_objects(struct kmem_cache *s, struct page *page, /* * Attempt to free all partial slabs on a node. - * This is called from kmem_cache_close(). We must be the last thread - * using the cache and therefore we do not need to lock anymore. + * This is called from __kmem_cache_shutdown(). We must take list_lock + * because sysfs file might still access partial list after the shutdowning. */ static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) { struct page *page, *h; + BUG_ON(irqs_disabled()); + spin_lock_irq(&n->list_lock); list_for_each_entry_safe(page, h, &n->partial, lru) { if (!page->inuse) { - __remove_partial(n, page); + remove_partial(n, page); discard_slab(s, page); } else { list_slab_objects(s, page, - "Objects remaining in %s on kmem_cache_close()"); + "Objects remaining in %s on __kmem_cache_shutdown()"); } } + spin_unlock_irq(&n->list_lock); } /* * Release all resources used by a slab cache. */ -static inline int kmem_cache_close(struct kmem_cache *s) +int __kmem_cache_shutdown(struct kmem_cache *s) { int node; struct kmem_cache_node *n; @@ -3476,16 +3510,9 @@ static inline int kmem_cache_close(struct kmem_cache *s) if (n->nr_partial || slabs_node(s, node)) return 1; } - free_percpu(s->cpu_slab); - free_kmem_cache_nodes(s); return 0; } -int __kmem_cache_shutdown(struct kmem_cache *s) -{ - return kmem_cache_close(s); -} - /******************************************************************** * Kmalloc subsystem *******************************************************************/ @@ -3980,7 +4007,7 @@ int __kmem_cache_create(struct kmem_cache *s, unsigned long flags) memcg_propagate_slab_attrs(s); err = sysfs_slab_add(s); if (err) - kmem_cache_close(s); + __kmem_cache_release(s); return err; } @@ -4816,16 +4843,16 @@ SLAB_ATTR_RO(total_objects); static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) { - return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE)); + return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS)); } static ssize_t sanity_checks_store(struct kmem_cache *s, const char *buf, size_t length) { - s->flags &= ~SLAB_DEBUG_FREE; + s->flags &= ~SLAB_CONSISTENCY_CHECKS; if (buf[0] == '1') { s->flags &= ~__CMPXCHG_DOUBLE; - s->flags |= SLAB_DEBUG_FREE; + s->flags |= SLAB_CONSISTENCY_CHECKS; } return length; } @@ -4869,7 +4896,6 @@ static ssize_t red_zone_store(struct kmem_cache *s, s->flags &= ~SLAB_RED_ZONE; if (buf[0] == '1') { - s->flags &= ~__CMPXCHG_DOUBLE; s->flags |= SLAB_RED_ZONE; } calculate_sizes(s, -1); @@ -4890,7 +4916,6 @@ static ssize_t poison_store(struct kmem_cache *s, s->flags &= ~SLAB_POISON; if (buf[0] == '1') { - s->flags &= ~__CMPXCHG_DOUBLE; s->flags |= SLAB_POISON; } calculate_sizes(s, -1); @@ -5360,7 +5385,7 @@ static char *create_unique_id(struct kmem_cache *s) *p++ = 'd'; if (s->flags & SLAB_RECLAIM_ACCOUNT) *p++ = 'a'; - if (s->flags & SLAB_DEBUG_FREE) + if (s->flags & SLAB_CONSISTENCY_CHECKS) *p++ = 'F'; if (!(s->flags & SLAB_NOTRACK)) *p++ = 't'; |