Messages in this thread Patch in this message | | | Date | Tue, 27 Jan 2009 18:59:46 -0800 (PST) | From | David Rientjes <> | Subject | [patch] slub: fix per cpu kmem_cache_cpu array memory leak |
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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> --- mm/slub.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/mm/slub.c b/mm/slub.c --- a/mm/slub.c +++ b/mm/slub.c @@ -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) { 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); return; }
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