slab: alien caches must not be initialized if the allocation of the alien cache failed

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: 49dfc304ba ("slab: use the lock on alien_cache, instead of the lock on array_cache")
Fixes: c8522a3a58 ("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>
This commit is contained in:
Christoph Lameter 2019-01-08 15:23:00 -08:00 committed by Linus Torvalds
parent ba4a45746c
commit 09c2e76ed7
1 changed files with 4 additions and 2 deletions

View File

@ -666,8 +666,10 @@ 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;
}