memcg: avoid vmpressure oops when memcg disabled

A CONFIG_MEMCG=y kernel booted with "cgroup_disable=memory" crashes on a
NULL memcg (but non-NULL root_mem_cgroup) when vmpressure kicks in.
Here's the patch I use to avoid that, but you might prefer a test on
mem_cgroup_disabled() somewhere.

Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: David S. Miller <davem@davemloft.net>
Cc: Vladimir Davydov <vdavydov@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Hugh Dickins 2016-01-14 15:21:37 -08:00 committed by Linus Torvalds
parent ef12947c9c
commit 686739f6af
1 changed files with 1 additions and 1 deletions

View File

@ -260,7 +260,7 @@ void vmpressure(gfp_t gfp, struct mem_cgroup *memcg, bool tree,
enum vmpressure_levels level;
/* For now, no users for root-level efficiency */
if (memcg == root_mem_cgroup)
if (!memcg || memcg == root_mem_cgroup)
return;
spin_lock(&vmpr->sr_lock);