diff options
Diffstat (limited to 'mm/slub.c')
| -rw-r--r-- | mm/slub.c | 75 |
1 files changed, 59 insertions, 16 deletions
diff --git a/mm/slub.c b/mm/slub.c index fca33abd6c42..d69934eac9e9 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -533,15 +533,32 @@ static void print_section(char *level, char *text, u8 *addr, metadata_access_disable(); } +/* + * See comment in calculate_sizes(). + */ +static inline bool freeptr_outside_object(struct kmem_cache *s) +{ + return s->offset >= s->inuse; +} + +/* + * Return offset of the end of info block which is inuse + free pointer if + * not overlapping with object. + */ +static inline unsigned int get_info_end(struct kmem_cache *s) +{ + if (freeptr_outside_object(s)) + return s->inuse + sizeof(void *); + else + return s->inuse; +} + static struct track *get_track(struct kmem_cache *s, void *object, enum track_item alloc) { struct track *p; - if (s->offset) - p = object + s->offset + sizeof(void *); - else - p = object + s->inuse; + p = object + get_info_end(s); return p + alloc; } @@ -644,6 +661,20 @@ static void slab_fix(struct kmem_cache *s, char *fmt, ...) va_end(args); } +static bool freelist_corrupted(struct kmem_cache *s, struct page *page, + void **freelist, void *nextfree) +{ + if ((s->flags & SLAB_CONSISTENCY_CHECKS) && + !check_valid_pointer(s, page, nextfree) && freelist) { + object_err(s, page, *freelist, "Freechain corrupt"); + *freelist = NULL; + slab_fix(s, "Isolate corrupted freechain"); + return true; + } + + return false; +} + static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) { unsigned int off; /* Offset of last byte */ @@ -668,10 +699,7 @@ static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) print_section(KERN_ERR, "Redzone ", p + s->object_size, s->inuse - s->object_size); - if (s->offset) - off = s->offset + sizeof(void *); - else - off = s->inuse; + off = get_info_end(s); if (s->flags & SLAB_STORE_USER) off += 2 * sizeof(struct track); @@ -762,7 +790,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page, * object address * Bytes of the object to be managed. * If the freepointer may overlay the object then the free - * pointer is the first word of the object. + * pointer is at the middle of the object. * * Poisoning uses 0x6b (POISON_FREE) and the last byte is * 0xa5 (POISON_END) @@ -796,11 +824,7 @@ static int check_bytes_and_report(struct kmem_cache *s, struct page *page, static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) { - unsigned long off = s->inuse; /* The end of info */ - - if (s->offset) - /* Freepointer is placed after the object. */ - off += sizeof(void *); + unsigned long off = get_info_end(s); /* The end of info */ if (s->flags & SLAB_STORE_USER) /* We also have user information there */ @@ -886,7 +910,7 @@ static int check_object(struct kmem_cache *s, struct page *page, check_pad_bytes(s, page, p); } - if (!s->offset && val == SLUB_RED_ACTIVE) + if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE) /* * Object and freepointer overlap. Cannot check * freepointer while object is allocated. @@ -1379,6 +1403,11 @@ static inline void inc_slabs_node(struct kmem_cache *s, int node, static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) {} +static bool freelist_corrupted(struct kmem_cache *s, struct page *page, + void **freelist, void *nextfree) +{ + return false; +} #endif /* CONFIG_SLUB_DEBUG */ /* @@ -2062,6 +2091,14 @@ static void deactivate_slab(struct kmem_cache *s, struct page *page, void *prior; unsigned long counters; + /* + * If 'nextfree' is invalid, it is possible that the object at + * 'freelist' is already corrupted. So isolate all objects + * starting at 'freelist'. + */ + if (freelist_corrupted(s, page, &freelist, nextfree)) + break; + do { prior = page->freelist; counters = page->counters; @@ -3558,6 +3595,11 @@ static int calculate_sizes(struct kmem_cache *s, int forced_order) * * This is the case if we do RCU, have a constructor or * destructor or are poisoning the objects. + * + * The assumption that s->offset >= s->inuse means free + * pointer is outside of the object is used in the + * freeptr_outside_object() function. If that is no + * longer true, the function needs to be modified. */ s->offset = size; size += sizeof(void *); @@ -5621,7 +5663,8 @@ static void memcg_propagate_slab_attrs(struct kmem_cache *s) */ if (buffer) buf = buffer; - else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf)) + else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf) && + !IS_ENABLED(CONFIG_SLUB_STATS)) buf = mbuf; else { buffer = (char *) get_zeroed_page(GFP_KERNEL); |