From: Peter Zijlstra <peterz@infradead.org>
To: Paul Menage <menage@google.com>
Cc: Mike Galbraith <efault@gmx.de>,
Miklos Vajna <vmiklos@frugalware.org>,
shenghui <crosslonelyover@gmail.com>,
kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org,
mingo@elte.hu, Greg KH <greg@kroah.com>,
Paul Turner <pjt@google.com>, Yong Zhang <yong.zhang0@gmail.com>,
Li Zefan <lizf@cn.fujitsu.com>,
Balbir Singh <balbir@linux.vnet.ibm.com>,
Srivatsa Vaddagiri <vatsa@in.ibm.com>
Subject: Re: [PATCH] sched, cgroup: Use exit hook to avoid use-after-free crash
Date: Mon, 03 Jan 2011 08:06:41 +0100 [thread overview]
Message-ID: <1294038401.2016.5.camel@laptop> (raw)
In-Reply-To: <AANLkTikTaYjm_xfzZkYO63Wovf9frjPAsuzwPXBtB-Tm@mail.gmail.com>
On Sat, 2010-12-25 at 20:59 +0000, Paul Menage wrote:
> While this patch is likely fine for solving the problem, it does add
> extra work into the task exit path.
>
> Could you instead just use the pre_destroy callback to return -EBUSY
> if there are still any tasks on the cfs_rq? That way there'd only be a
> penalty on cgroup destruction, which is a much rarer operation.
No, that's broken! That would mean userspace gets the cgroup-empty
notification thing and then encounters -EBUSY, which then forces it to
go poll the state, rendering the whole notification thing pointless.
next prev parent reply other threads:[~2011-01-03 7:06 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-29 7:10 [PATCH] avoid race condition in pick_next_task_fair in kernel/sched_fair.c shenghui
2010-06-29 10:43 ` Peter Zijlstra
2010-06-29 11:24 ` shenghui
2010-06-29 11:35 ` Peter Zijlstra
2010-06-29 12:44 ` shenghui
2010-12-19 2:03 ` Miklos Vajna
2010-12-22 0:22 ` Miklos Vajna
2010-12-22 8:29 ` Peter Zijlstra
2010-12-22 8:41 ` Peter Zijlstra
2010-12-22 8:41 ` Mike Galbraith
2010-12-22 9:07 ` Peter Zijlstra
2010-12-22 13:31 ` Miklos Vajna
2010-12-22 14:00 ` Peter Zijlstra
2010-12-22 14:11 ` Peter Zijlstra
2010-12-22 15:14 ` Miklos Vajna
2010-12-22 15:25 ` Peter Zijlstra
2010-12-22 17:08 ` Peter Zijlstra
2010-12-22 17:16 ` Ingo Molnar
2010-12-22 17:25 ` Peter Zijlstra
2010-12-22 20:36 ` Peter Zijlstra
2010-12-23 2:08 ` Yong Zhang
2010-12-23 12:12 ` Peter Zijlstra
2010-12-23 12:33 ` Peter Zijlstra
2010-12-23 18:24 ` Peter Zijlstra
[not found] ` <1293132304.6798.6.camel@marge.simson.net>
[not found] ` <1293132862.25981.22.camel@laptop>
[not found] ` <1293187425.7138.2.camel@marge.simson.net>
[not found] ` <1293188091.25981.200.camel@laptop>
[not found] ` <1293192999.18035.4.camel@marge.simson.net>
2010-12-24 15:59 ` [PATCH] sched, cgroup: Use exit hook to avoid use-after-free crash Peter Zijlstra
2010-12-24 16:40 ` Miklos Vajna
2010-12-24 16:48 ` Mike Galbraith
2010-12-24 17:07 ` Peter Zijlstra
2010-12-24 17:24 ` Mike Galbraith
2010-12-25 17:55 ` Balbir Singh
2010-12-25 20:59 ` Paul Menage
2011-01-03 7:06 ` Peter Zijlstra [this message]
2010-12-29 15:25 ` Ingo Molnar
2010-12-29 23:07 ` Miklos Vajna
2010-12-31 10:04 ` Mike Galbraith
2010-12-31 10:46 ` Miklos Vajna
2010-12-31 8:32 ` [PATCH] " Mike Galbraith
2011-01-03 8:21 ` Peter Zijlstra
2011-01-04 14:19 ` [tip:sched/core] sched, autogroup: Fix reference leak tip-bot for Mike Galbraith
2011-01-04 14:57 ` Oleg Nesterov
2011-01-04 19:06 ` Mike Galbraith
2011-01-19 19:04 ` [tip:sched/urgent] sched, cgroup: Use exit hook to avoid use-after-free crash tip-bot for Peter Zijlstra
2010-12-22 21:11 ` [PATCH] avoid race condition in pick_next_task_fair in kernel/sched_fair.c Miklos Vajna
2010-12-22 23:39 ` Miklos Vajna
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