Commit ef8b4520 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds

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: default avatarChristoph Lameter <clameter@sgi.com>
Acked-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
Cc: Matt Mackall <mpm@selenic.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0da7e01f
......@@ -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));
......
......@@ -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);
......
......@@ -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);
......
......@@ -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;
......
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