diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/slub.c | 26 |
1 files changed, 18 insertions, 8 deletions
diff --git a/mm/slub.c b/mm/slub.c index 51663a3c3c2..c9ab68881b4 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2241,7 +2241,7 @@ void *__kmalloc(size_t size, gfp_t flags) if (s) return slab_alloc(s, flags, -1, __builtin_return_address(0)); - return NULL; + return ZERO_SIZE_PTR; } EXPORT_SYMBOL(__kmalloc); @@ -2252,16 +2252,20 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node) if (s) return slab_alloc(s, flags, node, __builtin_return_address(0)); - return NULL; + return ZERO_SIZE_PTR; } EXPORT_SYMBOL(__kmalloc_node); #endif size_t ksize(const void *object) { - struct page *page = get_object_page(object); + struct page *page; struct kmem_cache *s; + if (object == ZERO_SIZE_PTR) + return 0; + + page = get_object_page(object); BUG_ON(!page); s = page->slab; BUG_ON(!s); @@ -2293,7 +2297,13 @@ void kfree(const void *x) struct kmem_cache *s; struct page *page; - if (!x) + /* + * This has to be an unsigned comparison. According to Linus + * some gcc version treat a pointer as a signed entity. Then + * this comparison would be true for all "negative" pointers + * (which would cover the whole upper half of the address space). + */ + if ((unsigned long)x <= (unsigned long)ZERO_SIZE_PTR) return; page = virt_to_head_page(x); @@ -2398,12 +2408,12 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags) void *ret; size_t ks; - if (unlikely(!p)) + if (unlikely(!p || p == ZERO_SIZE_PTR)) return kmalloc(new_size, flags); if (unlikely(!new_size)) { kfree(p); - return NULL; + return ZERO_SIZE_PTR; } ks = ksize(p); @@ -2652,7 +2662,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller) struct kmem_cache *s = get_slab(size, gfpflags); if (!s) - return NULL; + return ZERO_SIZE_PTR; return slab_alloc(s, gfpflags, -1, caller); } @@ -2663,7 +2673,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, struct kmem_cache *s = get_slab(size, gfpflags); if (!s) - return NULL; + return ZERO_SIZE_PTR; return slab_alloc(s, gfpflags, node, caller); } |