From: Andrew Morton <akpm@linux-foundation.org>
To: Li Zefan <lizf@cn.fujitsu.com>
Cc: Paul Menage <menage@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux-foundation.org>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Paul Jackson <pj@sgi.com>
Subject: Re: [PATCH] cgroup: fix a race condition in manipulating tsk->cg_list
Date: Wed, 16 Apr 2008 22:16:02 -0700 [thread overview]
Message-ID: <20080416221602.0a13b94b.akpm@linux-foundation.org> (raw)
In-Reply-To: <4806DBC9.3090607@cn.fujitsu.com>
On Thu, 17 Apr 2008 13:10:33 +0800 Li Zefan <lizf@cn.fujitsu.com> wrote:
> Andrew Morton wrote:
> > On Wed, 16 Apr 2008 21:17:34 -0700 "Paul Menage" <menage@google.com> wrote:
> >
> >> On Wed, Apr 16, 2008 at 9:11 PM, Andrew Morton
> >> <akpm@linux-foundation.org> wrote:
> >>> I don't fully understand the race. Both paths hold css_set_lock.
> >>>
> >>> Can you describe it in more detail please?
> >> Task A starts exiting, passes the check for unlinking current->cg_list.
> >
> > So cgroup_exit() sees !list_empty(tsk->cg_list)
> >
>
> cgroup_exit() sees list_empty(tsk->cg_list), then cgroup_enable_task_cg_list()
> links the task to the list, and then the task exited, so the list entry won't
> get deleted.
OK.
next prev parent reply other threads:[~2008-04-17 5:16 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-04-17 3:37 [PATCH] cgroup: fix a race condition in manipulating tsk->cg_list Li Zefan
2008-04-17 4:11 ` Andrew Morton
2008-04-17 4:17 ` Paul Menage
2008-04-17 4:59 ` Andrew Morton
2008-04-17 5:10 ` Li Zefan
2008-04-17 5:16 ` Andrew Morton [this message]
2008-04-17 5:20 ` Paul Menage
2008-04-17 4:18 ` Paul Menage
2008-04-17 4:28 ` Paul Menage
2008-04-17 5:04 ` Li Zefan
2008-04-17 5:16 ` Andrew Morton
2008-04-17 5:24 ` Paul Menage
2008-04-17 5:27 ` Li Zefan
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