Re: [PATCH] memcg: fix oops in mem_cgroup_shrink_usage

kamezawa.hiroyu
2008-08-06T16:20:15Z

----- Original Message -----
>Date: Wed, 6 Aug 2008 15:15:08 +0100 (BST)
>From: Hugh Dickins <hugh@veritas.com>
>To: Andrew Morton <akpm@linux-foundation.org>
>cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
> Balbir Singh <balbir@linux.vnet.ibm.com>, linux-kernel@vger.kernel.org
>Subject: [PATCH] memcg: fix oops in mem_cgroup_shrink_usage
>
>
>Got an oops in mem_cgroup_shrink_usage() when testing loop over tmpfs:
>yes, of course, loop0 has no mm: other entry points check but this didn't.
>
>Signed-off-by: Hugh Dickins <hugh@veritas.com>

Ahh, thank you!

-Kame

>---
>
> mm/memcontrol.c | 2 ++
> 1 file changed, 2 insertions(+)
>
>--- 2.6.27-rc2/mm/memcontrol.c 2008-08-06 08:36:20.000000000 +0100
>+++ linux/mm/memcontrol.c 2008-08-06 09:05:26.000000000 +0100
>@@ -796,6 +796,8 @@ int mem_cgroup_shrink_usage(struct mm_st
>
> if (mem_cgroup_subsys.disabled)
> return 0;
>+ if (!mm)
>+ return 0;
>
> rcu_read_lock();
> mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
>--
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