From: Tejun Heo <tj@kernel.org>
To: Li Zefan <lizf@cn.fujitsu.com>
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: Mon, 19 Dec 2011 09:13:07 -0800 [thread overview]
Message-ID: <20111219171307.GG24519@google.com> (raw)
In-Reply-To: <4EEAA923.5060104@cn.fujitsu.com>
On Fri, Dec 16, 2011 at 10:12:51AM +0800, Li Zefan wrote:
> 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>
Applied to cgroup/for-fixes-3.2. Will push to Linus in a couple of
days. It's already rc6 and a bit late tho.
Thank you.
--
tejun
prev parent reply other threads:[~2011-12-19 17:13 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
2011-12-19 17:13 ` Tejun Heo [this message]
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