git.ipfire.org Git - thirdparty/kernel/stable-queue.git/blob

   1 From 09c2e76ed734a1d36470d257a778aaba28e86531 Mon Sep 17 00:00:00 2001
   2 From: Christoph Lameter <cl@linux.com>
   3 Date: Tue, 8 Jan 2019 15:23:00 -0800
   4 Subject: slab: alien caches must not be initialized if the allocation of the alien cache failed
   5
   6 From: Christoph Lameter <cl@linux.com>
   7
   8 commit 09c2e76ed734a1d36470d257a778aaba28e86531 upstream.
   9
  10 Callers of __alloc_alien() check for NULL.  We must do the same check in
  11 __alloc_alien_cache to avoid NULL pointer dereferences on allocation
  12 failures.
  13
  14 Link: http://lkml.kernel.org/r/010001680f42f192-82b4e12e-1565-4ee0-ae1f-1e98974906aa-000000@email.amazonses.com
  15 Fixes: 49dfc304ba241 ("slab: use the lock on alien_cache, instead of the lock on array_cache")
  16 Fixes: c8522a3a5832b ("Slab: introduce alloc_alien")
  17 Signed-off-by: Christoph Lameter <cl@linux.com>
  18 Reported-by: syzbot+d6ed4ec679652b4fd4e4@syzkaller.appspotmail.com
  19 Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
  20 Cc: Pekka Enberg <penberg@kernel.org>
  21 Cc: David Rientjes <rientjes@google.com>
  22 Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
  23 Cc: <stable@vger.kernel.org>
  24 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  25 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  26 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  27
  28 ---
  29  mm/slab.c |    6 ++++--
  30  1 file changed, 4 insertions(+), 2 deletions(-)
  31
  32 --- a/mm/slab.c
  33 +++ b/mm/slab.c
  34 @@ -869,8 +869,10 @@ static struct alien_cache *__alloc_alien
  35         struct alien_cache *alc = NULL;
  36
  37         alc = kmalloc_node(memsize, gfp, node);
  38 -       init_arraycache(&alc->ac, entries, batch);
  39 -       spin_lock_init(&alc->lock);
  40 +       if (alc) {
  41 +               init_arraycache(&alc->ac, entries, batch);
  42 +               spin_lock_init(&alc->lock);
  43 +       }
  44         return alc;
  45  }
  46