Commit 3e6b11df authored Aug 13, 2013 by Andrey Vagin Committed by Linus Torvalds Aug 13, 2013

memcg: don't initialize kmem-cache destroying work for root caches



struct memcg_cache_params has a union.  Different parts of this union
are used for root and non-root caches.  A part with destroying work is
used only for non-root caches.

I fixed the same problem in another place v3.9-rc1-16204-gf101a94, but
didn't notice this one.

This patch fixes the kernel panic:

[   46.848187] BUG: unable to handle kernel paging request at 000000fffffffeb8
[   46.849026] IP: [<ffffffff811a484c>] kmem_cache_destroy_memcg_children+0x6c/0xc0
[   46.849092] PGD 0
[   46.849092] Oops: 0000 [#1] SMP
...

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Cc: Glauber Costa <glommer@openvz.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: <stable@vger.kernel.org>    [3.9.x]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 584d88b2

mm/memcontrol.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -3195,11 +3195,11 @@ int memcg_register_cache(struct mem_cgroup memcg, struct kmem_cache s,
		if (!s->memcg_params)
		return -ENOMEM;

		INIT_WORK(&s->memcg_params->destroy,
		kmem_cache_destroy_work_func);
		if (memcg) {
		s->memcg_params->memcg = memcg;
		s->memcg_params->root_cache = root_cache;
		INIT_WORK(&s->memcg_params->destroy,
		kmem_cache_destroy_work_func);
		} else
		s->memcg_params->is_root_cache = true;

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