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slub: fix per cpu kmem_cache_cpu array memory leak 

The per cpu array of kmem_cache_cpu structures accomodates
NR_KMEM_CACHE_CPU such structs.

When this array overflows and a struct is allocated by kmalloc(), it may
have an address at the upper bound of this array.  If this happens, it
does not get freed and the per cpu kmem_cache_cpu_free pointer will be out
of bounds after kmem_cache_destroy() or cpu offlining.

Cc: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This commit is contained in:
David Rientjes 2009-01-27 18:59:46 -08:00 committed by Pekka Enberg
parent a6525042bf
commit 3718909448
1 changed files with 1 additions and 1 deletions
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mm/slub.c
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@ -1996,7 +1996,7 @@ static struct kmem_cache_cpu *alloc_kmem_cache_cpu(struct kmem_cache *s,
static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu) static void free_kmem_cache_cpu(struct kmem_cache_cpu *c, int cpu)
{ {
if (c < per_cpu(kmem_cache_cpu, cpu) || if (c < per_cpu(kmem_cache_cpu, cpu) ||
c > per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) { c >= per_cpu(kmem_cache_cpu, cpu) + NR_KMEM_CACHE_CPU) {
kfree(c); kfree(c);
return; return;
} }