From: Mandeep Singh Baines <msb@chromium.org>
To: Tejun Heo <tj@kernel.org>
Cc: Mandeep Singh Baines <msb@chromium.org>,
Li Zefan <lizf@cn.fujitsu.com>,
LKML <linux-kernel@vger.kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Paul Menage <paul@paulmenage.org>
Subject: Re: [PATCH 2/5] cgroup: remove redundant get/put of task struct
Date: Tue, 20 Dec 2011 16:04:18 -0800 [thread overview]
Message-ID: <20111221000418.GY13529@google.com> (raw)
In-Reply-To: <20111220232326.GL10752@google.com>
Tejun Heo (tj@kernel.org) wrote:
> Hello,
>
> On Tue, Dec 20, 2011 at 03:14:30PM -0800, Mandeep Singh Baines wrote:
> > @@ -2287,14 +2280,12 @@ static int attach_task_by_pid(struct cgroup *cgrp, u64 pid, bool threadgroup)
> > cgroup_unlock();
> > return -EACCES;
> > }
> > - get_task_struct(tsk);
> > rcu_read_unlock();
>
> This is before threadgroup is locked. What guarantees @tsk doesn't go
> away once rcu is unlocked?
>
Nothing. D'oh. I'll remove the changes to attach_task_by_id and leave
the others.
> Thanks.
>
> --
> tejun
next prev parent reply other threads:[~2011-12-21 0:12 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-20 23:14 [PATCH 0/5] cgroup: some cleanups of cgroup_attach_proc Mandeep Singh Baines
2011-12-20 23:14 ` [PATCH 1/5 V3] cgroup: remove redundate get/put of old css_set from migrate Mandeep Singh Baines
2011-12-20 23:18 ` Tejun Heo
2011-12-20 23:41 ` Mandeep Singh Baines
2011-12-20 23:42 ` Tejun Heo
2011-12-20 23:46 ` Tejun Heo
2011-12-21 1:10 ` Li Zefan
2011-12-20 23:14 ` [PATCH 2/5] cgroup: remove redundant get/put of task struct Mandeep Singh Baines
2011-12-20 23:23 ` Tejun Heo
2011-12-21 0:04 ` Mandeep Singh Baines [this message]
2011-12-20 23:14 ` [PATCH 3/5] cgroup: only need to check oldcgrp==newgrp once Mandeep Singh Baines
2011-12-21 1:29 ` Li Zefan
2011-12-20 23:14 ` [PATCH 4/5] cgroup: remove extra calls to find_existing_css_set Mandeep Singh Baines
2011-12-20 23:30 ` Tejun Heo
2011-12-20 23:47 ` Mandeep Singh Baines
2011-12-20 23:14 ` [PATCH 5/5] cgroup: separate out cgroup_attach_proc error handling code Mandeep Singh Baines
2011-12-20 23:35 ` Tejun Heo
2011-12-21 0:02 ` Mandeep Singh Baines
2011-12-21 0:13 ` Tejun Heo
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