From becfda68abca673d61d5cc953e8e099816db99d9 Mon Sep 17 00:00:00 2001 From: Laura Abbott Date: Tue, 15 Mar 2016 14:55:06 -0700 Subject: [PATCH] slub: convert SLAB_DEBUG_FREE to SLAB_CONSISTENCY_CHECKS SLAB_DEBUG_FREE allows expensive consistency checks at free to be turned on or off. Expand its use to be able to turn off all consistency checks. This gives a nice speed up if you only want features such as poisoning or tracing. Credit to Mathias Krause for the original work which inspired this series Signed-off-by: Laura Abbott Acked-by: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Cc: Kees Cook Cc: Mathias Krause Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/vm/slub.txt | 4 +- include/linux/slab.h | 2 +- mm/slab.h | 5 ++- mm/slub.c | 94 ++++++++++++++++++++++++--------------- tools/vm/slabinfo.c | 2 +- 5 files changed, 66 insertions(+), 41 deletions(-) diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt index f0d340959319..84652419bff2 100644 --- a/Documentation/vm/slub.txt +++ b/Documentation/vm/slub.txt @@ -35,8 +35,8 @@ slub_debug=, Enable options only for select slabs Possible debug options are - F Sanity checks on (enables SLAB_DEBUG_FREE. Sorry - SLAB legacy issues) + F Sanity checks on (enables SLAB_DEBUG_CONSISTENCY_CHECKS + Sorry SLAB legacy issues) Z Red zoning P Poisoning (object and padding) U User tracking (free and alloc) diff --git a/include/linux/slab.h b/include/linux/slab.h index 5d49f0c60dcb..e4b568738ca3 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -20,7 +20,7 @@ * Flags to pass to kmem_cache_create(). * The ones marked DEBUG are only valid if CONFIG_DEBUG_SLAB is set. */ -#define SLAB_DEBUG_FREE 0x00000100UL /* DEBUG: Perform (expensive) checks on free */ +#define SLAB_CONSISTENCY_CHECKS 0x00000100UL /* DEBUG: Perform (expensive) checks on alloc/free */ #define SLAB_RED_ZONE 0x00000400UL /* DEBUG: Red zone objs in a cache */ #define SLAB_POISON 0x00000800UL /* DEBUG: Poison objects */ #define SLAB_HWCACHE_ALIGN 0x00002000UL /* Align objs on cache lines */ diff --git a/mm/slab.h b/mm/slab.h index e880bbe91973..b7934361f026 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -125,7 +125,7 @@ static inline unsigned long kmem_cache_flags(unsigned long object_size, #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) #elif defined(CONFIG_SLUB_DEBUG) #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ - SLAB_TRACE | SLAB_DEBUG_FREE) + SLAB_TRACE | SLAB_CONSISTENCY_CHECKS) #else #define SLAB_DEBUG_FLAGS (0) #endif @@ -311,7 +311,8 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x) * to not do even the assignment. In that case, slab_equal_or_root * will also be a constant. */ - if (!memcg_kmem_enabled() && !unlikely(s->flags & SLAB_DEBUG_FREE)) + if (!memcg_kmem_enabled() && + !unlikely(s->flags & SLAB_CONSISTENCY_CHECKS)) return s; page = virt_to_head_page(x); diff --git a/mm/slub.c b/mm/slub.c index 744d29b43bf6..9cde663bbb10 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -160,7 +160,7 @@ 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) /* @@ -1007,20 +1007,32 @@ 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) @@ -1043,39 +1055,21 @@ bad: return 0; } -/* 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) +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; - unsigned long uninitialized_var(flags); - int ret = 0; - - spin_lock_irqsave(&n->list_lock, flags); - slab_lock(page); - - if (!check_slab(s, page)) - goto out; - -next_object: - cnt++; - if (!check_valid_pointer(s, page, object)) { slab_err(s, page, "Invalid object pointer 0x%p", object); - goto out; + return 0; } if (on_freelist(s, page, object)) { object_err(s, page, object, "Object already free"); - goto out; + return 0; } if (!check_object(s, page, object, SLUB_RED_ACTIVE)) - goto out; + return 0; if (unlikely(s != page->slab_cache)) { if (!PageSlab(page)) { @@ -1088,7 +1082,37 @@ next_object: } else object_err(s, page, object, "page slab pointer corrupt."); - goto out; + 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) @@ -1145,7 +1169,7 @@ 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; @@ -1449,7 +1473,7 @@ 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); @@ -4769,16 +4793,16 @@ 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; } @@ -5313,7 +5337,7 @@ 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'; diff --git a/tools/vm/slabinfo.c b/tools/vm/slabinfo.c index 86e698d07e20..1889163f2f05 100644 --- a/tools/vm/slabinfo.c +++ b/tools/vm/slabinfo.c @@ -135,7 +135,7 @@ static void usage(void) "\nValid debug options (FZPUT may be combined)\n" "a / A Switch on all debug options (=FZUP)\n" "- Switch off all debug options\n" - "f / F Sanity Checks (SLAB_DEBUG_FREE)\n" + "f / F Sanity Checks (SLAB_CONSISTENCY_CHECKS)\n" "z / Z Redzoning\n" "p / P Poisoning\n" "u / U Tracking\n" -- 2.20.1