diff options
| author | Christoph Lameter <clameter@sgi.com> | 2007-10-16 01:24:46 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-10-16 09:42:53 -0700 |
| commit | ef8b4520bd9f8294ffce9abd6158085bde5dc902 (patch) | |
| tree | c099a16691ac06208f4d3d65b71e7adaf7361fcd | |
| parent | 0da7e01f5f37f441cccd7c8c0586e06db0981907 (diff) | |
| download | lwn-ef8b4520bd9f8294ffce9abd6158085bde5dc902.tar.gz lwn-ef8b4520bd9f8294ffce9abd6158085bde5dc902.zip | |
Slab allocators: fail if ksize is called with a NULL parameter
A NULL pointer means that the object was not allocated. One cannot
determine the size of an object that has not been allocated. Currently we
return 0 but we really should BUG() on attempts to determine the size of
something nonexistent.
krealloc() interprets NULL to mean a zero sized object. Handle that
separately in krealloc().
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/slab.c | 3 | ||||
| -rw-r--r-- | mm/slob.c | 3 | ||||
| -rw-r--r-- | mm/slub.c | 3 | ||||
| -rw-r--r-- | mm/util.c | 6 |
4 files changed, 10 insertions, 5 deletions
diff --git a/mm/slab.c b/mm/slab.c index 6f6abef83a1a..1b240a3029d6 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -4446,7 +4446,8 @@ const struct seq_operations slabstats_op = { */ size_t ksize(const void *objp) { - if (unlikely(ZERO_OR_NULL_PTR(objp))) + BUG_ON(!objp); + if (unlikely(objp == ZERO_SIZE_PTR)) return 0; return obj_size(virt_to_cache(objp)); diff --git a/mm/slob.c b/mm/slob.c index a886e83e17ef..de5d5563a46c 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -484,7 +484,8 @@ size_t ksize(const void *block) { struct slob_page *sp; - if (unlikely(ZERO_OR_NULL_PTR(block))) + BUG_ON(!block); + if (unlikely(block == ZERO_SIZE_PTR)) return 0; sp = (struct slob_page *)virt_to_page(block); diff --git a/mm/slub.c b/mm/slub.c index b7d3664fa3a9..d7c044dbd157 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2449,7 +2449,8 @@ size_t ksize(const void *object) struct page *page; struct kmem_cache *s; - if (unlikely(ZERO_OR_NULL_PTR(object))) + BUG_ON(!object); + if (unlikely(object == ZERO_SIZE_PTR)) return 0; page = get_object_page(object); diff --git a/mm/util.c b/mm/util.c index bf340d806868..5f64026cbb4d 100644 --- a/mm/util.c +++ b/mm/util.c @@ -81,14 +81,16 @@ EXPORT_SYMBOL(kmemdup); void *krealloc(const void *p, size_t new_size, gfp_t flags) { void *ret; - size_t ks; + size_t ks = 0; if (unlikely(!new_size)) { kfree(p); return ZERO_SIZE_PTR; } - ks = ksize(p); + if (p) + ks = ksize(p); + if (ks >= new_size) return (void *)p; |