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From: Minchan Kim <minchan.kim@gmail.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Rientjes <rientjes@google.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 02/11] oom: oom_kill_process() doesn't select kthread child
Date: Thu, 1 Jul 2010 22:38:46 +0900	[thread overview]
Message-ID: <20100701133846.GA16383@barrios-desktop> (raw)
In-Reply-To: <20100701085011.DA13.A69D9226@jp.fujitsu.com>

On Thu, Jul 01, 2010 at 09:07:02AM +0900, KOSAKI Motohiro wrote:
> > On Wed, Jun 30, 2010 at 06:27:52PM +0900, KOSAKI Motohiro wrote:
> > > Now, select_bad_process() have PF_KTHREAD check, but oom_kill_process
> > > doesn't. It mean oom_kill_process() may choose wrong task, especially,
> > > when the child are using use_mm().
> > 
> > Is it possible child is kthread even though parent isn't kthread?
> 
> Usually unhappen. but crappy driver can do any strange thing freely.
> As I said, oom code should have conservative assumption as far as possible.

Okay. You change the check with oom_unkillable_task at last. 
The oom_unkillable_task is generic function so that the kthread check in
oom_kill_process is tivial, I think. 

Reviewed-by: Minchan Kim <minchan.kim@gmail.com>


> 
> 
> 

-- 
Kind regards,
Minchan Kim

WARNING: multiple messages have this Message-ID (diff)
From: Minchan Kim <minchan.kim@gmail.com>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	linux-mm <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	David Rientjes <rientjes@google.com>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH 02/11] oom: oom_kill_process() doesn't select kthread child
Date: Thu, 1 Jul 2010 22:38:46 +0900	[thread overview]
Message-ID: <20100701133846.GA16383@barrios-desktop> (raw)
In-Reply-To: <20100701085011.DA13.A69D9226@jp.fujitsu.com>

On Thu, Jul 01, 2010 at 09:07:02AM +0900, KOSAKI Motohiro wrote:
> > On Wed, Jun 30, 2010 at 06:27:52PM +0900, KOSAKI Motohiro wrote:
> > > Now, select_bad_process() have PF_KTHREAD check, but oom_kill_process
> > > doesn't. It mean oom_kill_process() may choose wrong task, especially,
> > > when the child are using use_mm().
> > 
> > Is it possible child is kthread even though parent isn't kthread?
> 
> Usually unhappen. but crappy driver can do any strange thing freely.
> As I said, oom code should have conservative assumption as far as possible.

Okay. You change the check with oom_unkillable_task at last. 
The oom_unkillable_task is generic function so that the kthread check in
oom_kill_process is tivial, I think. 

Reviewed-by: Minchan Kim <minchan.kim@gmail.com>


> 
> 
> 

-- 
Kind regards,
Minchan Kim

--
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  reply	other threads:[~2010-07-01 13:38 UTC|newest]

Thread overview: 72+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-06-30  9:25 [mmotm 0611][PATCH 00/11] various OOM bugfixes v3 KOSAKI Motohiro
2010-06-30  9:25 ` KOSAKI Motohiro
2010-06-30  9:27 ` [PATCH 01/11] oom: don't try to kill oom_unkillable child KOSAKI Motohiro
2010-06-30  9:27   ` KOSAKI Motohiro
2010-06-30  9:27 ` [PATCH 02/11] oom: oom_kill_process() doesn't select kthread child KOSAKI Motohiro
2010-06-30  9:27   ` KOSAKI Motohiro
2010-06-30 13:55   ` Minchan Kim
2010-06-30 13:55     ` Minchan Kim
2010-07-01  0:07     ` KOSAKI Motohiro
2010-07-01  0:07       ` KOSAKI Motohiro
2010-07-01 13:38       ` Minchan Kim [this message]
2010-07-01 13:38         ` Minchan Kim
2010-06-30  9:28 ` [PATCH 03/11] oom: make oom_unkillable_task() helper function KOSAKI Motohiro
2010-06-30  9:28   ` KOSAKI Motohiro
2010-06-30 14:19   ` Minchan Kim
2010-06-30 14:19     ` Minchan Kim
2010-07-01  0:07     ` KOSAKI Motohiro
2010-07-01  0:07       ` KOSAKI Motohiro
2010-06-30  9:29 ` [PATCH 04/11] oom: oom_kill_process() need to check p is unkillable KOSAKI Motohiro
2010-06-30  9:29   ` KOSAKI Motohiro
2010-06-30 13:57   ` Minchan Kim
2010-06-30 13:57     ` Minchan Kim
2010-06-30  9:30 ` [PATCH 05/11] oom: /proc/<pid>/oom_score treat kernel thread honestly KOSAKI Motohiro
2010-06-30  9:30   ` KOSAKI Motohiro
2010-06-30 14:03   ` Minchan Kim
2010-06-30 14:03     ` Minchan Kim
2010-07-01  0:07     ` KOSAKI Motohiro
2010-07-01  0:07       ` KOSAKI Motohiro
2010-07-01 14:36       ` Minchan Kim
2010-07-01 14:36         ` Minchan Kim
2010-06-30  9:31 ` [PATCH 06/11] oom: kill duplicate OOM_DISABLE check KOSAKI Motohiro
2010-06-30  9:31   ` KOSAKI Motohiro
2010-06-30 14:10   ` Minchan Kim
2010-06-30 14:10     ` Minchan Kim
2010-06-30  9:31 ` [PATCH 07/11] oom: move OOM_DISABLE check from oom_kill_task to out_of_memory() KOSAKI Motohiro
2010-06-30  9:31   ` KOSAKI Motohiro
2010-06-30 14:20   ` Minchan Kim
2010-06-30 14:20     ` Minchan Kim
2010-07-01  0:07     ` KOSAKI Motohiro
2010-07-01  0:07       ` KOSAKI Motohiro
2010-06-30  9:32 ` [PATCH 08/11] oom: cleanup has_intersects_mems_allowed() KOSAKI Motohiro
2010-06-30  9:32   ` KOSAKI Motohiro
2010-06-30  9:32 ` [PATCH 09/11] oom: remove child->mm check from oom_kill_process() KOSAKI Motohiro
2010-06-30  9:32   ` KOSAKI Motohiro
2010-06-30 14:30   ` Minchan Kim
2010-06-30 14:30     ` Minchan Kim
2010-06-30  9:33 ` [PATCH 10/11] oom: give the dying task a higher priority KOSAKI Motohiro
2010-06-30  9:33   ` KOSAKI Motohiro
2010-06-30  9:35   ` KOSAKI Motohiro
2010-06-30  9:35     ` KOSAKI Motohiro
2010-06-30 14:40     ` Minchan Kim
2010-06-30 14:40       ` Minchan Kim
2010-07-02 21:49   ` Andrew Morton
2010-07-02 21:49     ` Andrew Morton
2010-07-06  0:49     ` KOSAKI Motohiro
2010-07-06  0:49       ` KOSAKI Motohiro
2010-07-06  0:50       ` [PATCH 1/2] security: add const to security_task_setscheduler() KOSAKI Motohiro
2010-07-06  0:50         ` KOSAKI Motohiro
2010-07-06  0:51       ` [PATCH 2/2] sched: make sched_param arugment static variables in some sched_setscheduler() caller KOSAKI Motohiro
2010-07-06  0:51         ` KOSAKI Motohiro
2010-07-06 22:13         ` Steven Rostedt
2010-07-06 22:13           ` Steven Rostedt
2010-07-06 23:12           ` Andrew Morton
2010-07-06 23:12             ` Andrew Morton
2010-07-06 23:49             ` Steven Rostedt
2010-07-06 23:49               ` Steven Rostedt
2010-07-07  0:02               ` Andrew Morton
2010-07-07  0:02                 ` Andrew Morton
2010-07-07 19:43                 ` Peter Zijlstra
2010-07-07 19:43                   ` Peter Zijlstra
2010-06-30  9:34 ` [PATCH 11/11] oom: multi threaded process coredump don't make deadlock KOSAKI Motohiro
2010-06-30  9:34   ` KOSAKI Motohiro

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