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authorChristoph Lameter <cl@linux.com>2019-01-09 02:23:00 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-17 00:04:33 +0300
commitf928ca3917478d5f01e49c96f172dbe4c843d4c1 (patch)
treeba176ab06c1c57c9c7f44b3d4b4315b256054b41
parent33c96bc68ff377064b18cd4bc821095b96a41e05 (diff)
downloadlinux-f928ca3917478d5f01e49c96f172dbe4c843d4c1.tar.xz
slab: alien caches must not be initialized if the allocation of the alien cache failed
commit 09c2e76ed734a1d36470d257a778aaba28e86531 upstream. Callers of __alloc_alien() check for NULL. We must do the same check in __alloc_alien_cache to avoid NULL pointer dereferences on allocation failures. Link: http://lkml.kernel.org/r/010001680f42f192-82b4e12e-1565-4ee0-ae1f-1e98974906aa-000000@email.amazonses.com Fixes: 49dfc304ba241 ("slab: use the lock on alien_cache, instead of the lock on array_cache") Fixes: c8522a3a5832b ("Slab: introduce alloc_alien") Signed-off-by: Christoph Lameter <cl@linux.com> Reported-by: syzbot+d6ed4ec679652b4fd4e4@syzkaller.appspotmail.com Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: David Rientjes <rientjes@google.com> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--mm/slab.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/slab.c b/mm/slab.c
index d73c7a4820a4..fad6839e8eab 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -679,8 +679,10 @@ static struct alien_cache *__alloc_alien_cache(int node, int entries,
struct alien_cache *alc = NULL;
alc = kmalloc_node(memsize, gfp, node);
- init_arraycache(&alc->ac, entries, batch);
- spin_lock_init(&alc->lock);
+ if (alc) {
+ init_arraycache(&alc->ac, entries, batch);
+ spin_lock_init(&alc->lock);
+ }
return alc;
}