From: Li Zefan <lizf@cn.fujitsu.com>
To: Tejun Heo <tj@kernel.org>
Cc: Mandeep Singh Baines <msb@chromium.org>,
linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
stable@kernel.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Paul Menage <paul@paulmenage.org>,
Olof Johansson <olofj@chromium.org>
Subject: Re: [PATCH] cgroups: fix a css_set not found bug in cgroup_attach_proc
Date: Fri, 16 Dec 2011 10:12:51 +0800 [thread overview]
Message-ID: <4EEAA923.5060104@cn.fujitsu.com> (raw)
In-Reply-To: <20111215212329.GH32002@google.com>
Tejun Heo wrote:
> On Thu, Dec 15, 2011 at 11:36:43AM -0800, Mandeep Singh Baines wrote:
>> There is a BUG when migrating a PF_EXITING proc. Since css_set_prefetch()
>> is not called for the PF_EXITING case, find_existing_css_set() will return
>> NULL inside cgroup_task_migrate() causing a BUG.
>>
>> This bug is easy to reproduce. Create a zombie and echo its pid to
>> cgroup.procs.
>>
>> $ cat zombie.c
>> \#include <unistd.h>
>>
>> int main()
>> {
>> if (fork())
>> pause();
>> return 0;
>> }
>> $
>>
>> We are hitting this bug pretty regularly on ChromeOS.
>>
>> This bug is already fixed by Tejun Heo's cgroup patchset which is
>> targetted for the next merge window:
>>
>> https://lkml.org/lkml/2011/11/1/356
>>
>> I've create a smaller patch here which just fixes this bug so that a
>> fix can be merged into the current release and stable.
>
> Looks safe to me. Li?
>
It should be fine.
Reviewed-by: Li Zefan <lizf@cn.fujitsu.com>
next prev parent reply other threads:[~2011-12-16 2:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-15 19:36 [PATCH] cgroups: fix a css_set not found bug in cgroup_attach_proc Mandeep Singh Baines
2011-12-15 21:23 ` Tejun Heo
2011-12-16 2:12 ` Li Zefan [this message]
2011-12-19 17:13 ` Tejun Heo
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