Commit 4d7868e6 authored by Christoph Lameter's avatar Christoph Lameter Committed by Pekka Enberg

slub: Do not dereference NULL pointer in node_match

The variables accessed in slab_alloc are volatile and therefore
the page pointer passed to node_match can be NULL. The processing
of data in slab_alloc is tentative until either the cmpxhchg
succeeds or the __slab_alloc slowpath is invoked. Both are
able to perform the same allocation from the freelist.

Check for the NULL pointer in node_match.

A false positive will lead to a retry of the loop in __slab_alloc.
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
parent 338b2642
...@@ -2042,7 +2042,7 @@ static void flush_all(struct kmem_cache *s) ...@@ -2042,7 +2042,7 @@ static void flush_all(struct kmem_cache *s)
static inline int node_match(struct page *page, int node) static inline int node_match(struct page *page, int node)
{ {
#ifdef CONFIG_NUMA #ifdef CONFIG_NUMA
if (node != NUMA_NO_NODE && page_to_nid(page) != node) if (!page || (node != NUMA_NO_NODE && page_to_nid(page) != node))
return 0; return 0;
#endif #endif
return 1; return 1;
......
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