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From: Richard Weinberger <richard@nod.at>
To: linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 08/10] um: Fix possible race on task->mm
Date: Sat, 24 Mar 2012 11:12:12 +0000	[thread overview]
Message-ID: <4F6DAC0C.4010203@nod.at> (raw)
In-Reply-To: <20120324103050.GH29067@lizard>

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Am 24.03.2012 11:30, schrieb Anton Vorontsov:
> Checking for task->mm is dangerous as ->mm might disappear (exit_mm()
> assigns NULL under task_lock(), so tasklist lock is not enough).
> 
> We can't use get_task_mm()/mmput() pair as mmput() might sleep,
> so let's take the task lock while we care about its mm.
> 
> Note that we should also use find_lock_task_mm() to check all process'
> threads for a valid mm, but for uml we'll do it in a separate patch.
> 
> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard


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WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard@nod.at>
To: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Oleg Nesterov <oleg@redhat.com>,
	Russell King <linux@arm.linux.org.uk>,
	Mike Frysinger <vapier@gentoo.org>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mundt <lethal@linux-sh.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	John Stultz <john.stultz@linaro.org>,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	uclinux-dist-devel@blackfin.uclinux.org,
	linuxppc-dev@lists.ozlabs.org, linux-sh@vger.kernel.org,
	user-mode-linux-devel@lists.sourceforge.net, linux-mm@kvack.org
Subject: Re: [PATCH 08/10] um: Fix possible race on task->mm
Date: Sat, 24 Mar 2012 12:12:12 +0100	[thread overview]
Message-ID: <4F6DAC0C.4010203@nod.at> (raw)
In-Reply-To: <20120324103050.GH29067@lizard>

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Am 24.03.2012 11:30, schrieb Anton Vorontsov:
> Checking for task->mm is dangerous as ->mm might disappear (exit_mm()
> assigns NULL under task_lock(), so tasklist lock is not enough).
> 
> We can't use get_task_mm()/mmput() pair as mmput() might sleep,
> so let's take the task lock while we care about its mm.
> 
> Note that we should also use find_lock_task_mm() to check all process'
> threads for a valid mm, but for uml we'll do it in a separate patch.
> 
> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard


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WARNING: multiple messages have this Message-ID (diff)
From: Richard Weinberger <richard@nod.at>
To: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Mike Frysinger <vapier@gentoo.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	user-mode-linux-devel@lists.sourceforge.net,
	linux-sh@vger.kernel.org, Oleg Nesterov <oleg@redhat.com>,
	linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	Paul Mundt <lethal@linux-sh.org>,
	John Stultz <john.stultz@linaro.org>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	uclinux-dist-devel@blackfin.uclinux.org,
	Russell King <linux@arm.linux.org.uk>,
	Andrew Morton <akpm@linux-foundation.org>,
	linuxppc-dev@lists.ozlabs.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 08/10] um: Fix possible race on task->mm
Date: Sat, 24 Mar 2012 12:12:12 +0100	[thread overview]
Message-ID: <4F6DAC0C.4010203@nod.at> (raw)
In-Reply-To: <20120324103050.GH29067@lizard>

[-- Attachment #1: Type: text/plain, Size: 608 bytes --]

Am 24.03.2012 11:30, schrieb Anton Vorontsov:
> Checking for task->mm is dangerous as ->mm might disappear (exit_mm()
> assigns NULL under task_lock(), so tasklist lock is not enough).
> 
> We can't use get_task_mm()/mmput() pair as mmput() might sleep,
> so let's take the task lock while we care about its mm.
> 
> Note that we should also use find_lock_task_mm() to check all process'
> threads for a valid mm, but for uml we'll do it in a separate patch.
> 
> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard


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WARNING: multiple messages have this Message-ID (diff)
From: richard@nod.at (Richard Weinberger)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 08/10] um: Fix possible race on task->mm
Date: Sat, 24 Mar 2012 12:12:12 +0100	[thread overview]
Message-ID: <4F6DAC0C.4010203@nod.at> (raw)
In-Reply-To: <20120324103050.GH29067@lizard>

Am 24.03.2012 11:30, schrieb Anton Vorontsov:
> Checking for task->mm is dangerous as ->mm might disappear (exit_mm()
> assigns NULL under task_lock(), so tasklist lock is not enough).
> 
> We can't use get_task_mm()/mmput() pair as mmput() might sleep,
> so let's take the task lock while we care about its mm.
> 
> Note that we should also use find_lock_task_mm() to check all process'
> threads for a valid mm, but for uml we'll do it in a separate patch.
> 
> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

Acked-by: Richard Weinberger <richard@nod.at>

Thanks,
//richard

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  reply	other threads:[~2012-03-24 11:12 UTC|newest]

Thread overview: 133+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-24 10:26 [PATCH v2 0/10] Fixes for common mistakes w/ for_each_process and task->mm Anton Vorontsov
2012-03-24 10:26 ` Anton Vorontsov
2012-03-24 10:26 ` Anton Vorontsov
2012-03-24 10:26 ` Anton Vorontsov
2012-03-24 10:26 ` Anton Vorontsov
2012-03-24 10:27 ` [PATCH 01/10] cpu: Introduce clear_tasks_mm_cpumask() helper Anton Vorontsov
2012-03-24 10:27   ` Anton Vorontsov
2012-03-24 10:27   ` Anton Vorontsov
2012-03-24 10:27   ` Anton Vorontsov
2012-03-24 10:27   ` Anton Vorontsov
2012-03-24 12:43   ` Peter Zijlstra
2012-03-24 12:43     ` Peter Zijlstra
2012-03-24 12:43     ` Peter Zijlstra
2012-03-24 12:43     ` Peter Zijlstra
2012-03-24 12:43     ` Peter Zijlstra
2012-03-24 16:43     ` [PATCH v2.1 " Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-25 17:42       ` Oleg Nesterov
2012-03-25 17:42         ` Oleg Nesterov
2012-03-25 17:42         ` Oleg Nesterov
2012-03-25 17:42         ` Oleg Nesterov
2012-03-25 17:42         ` Oleg Nesterov
2012-03-26  7:59         ` Peter Zijlstra
2012-03-26  7:59           ` Peter Zijlstra
2012-03-26  7:59           ` Peter Zijlstra
2012-03-26  7:59           ` Peter Zijlstra
2012-03-26  7:59           ` Peter Zijlstra
2012-03-26 17:04           ` Oleg Nesterov
2012-03-26 17:04             ` Oleg Nesterov
2012-03-26 17:04             ` Oleg Nesterov
2012-03-26 17:04             ` Oleg Nesterov
2012-03-26 17:04             ` Oleg Nesterov
2012-03-26 17:23             ` Peter Zijlstra
2012-03-26 17:23               ` Peter Zijlstra
2012-03-26 17:23               ` Peter Zijlstra
2012-03-26 17:23               ` Peter Zijlstra
2012-03-26 17:23               ` Peter Zijlstra
2012-03-28  0:01         ` Benjamin Herrenschmidt
2012-03-28  0:01           ` Benjamin Herrenschmidt
2012-03-28  0:01           ` Benjamin Herrenschmidt
2012-03-28  0:01           ` Benjamin Herrenschmidt
2012-03-28  0:01           ` Benjamin Herrenschmidt
2012-03-28  0:01           ` Benjamin Herrenschmidt
2012-03-24 10:28 ` [PATCH 02/10] arm: Use clear_tasks_mm_cpumask() Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28 ` [PATCH 03/10] powerpc: " Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28 ` [PATCH 04/10] sh: " Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:28   ` Anton Vorontsov
2012-03-24 10:29 ` [PATCH 05/10] blackfin: A couple of task->mm handling fixes Anton Vorontsov
2012-03-24 10:29   ` Anton Vorontsov
2012-03-24 10:29   ` Anton Vorontsov
2012-03-24 10:29   ` Anton Vorontsov
2012-03-24 10:29   ` Anton Vorontsov
2012-03-24 10:30 ` [PATCH 06/10] blackfin: Fix possible deadlock in decode_address() Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30 ` [PATCH 07/10] um: Should hold tasklist_lock while traversing processes Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 11:12   ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 12:48   ` Peter Zijlstra
2012-03-24 12:48     ` Peter Zijlstra
2012-03-24 12:48     ` Peter Zijlstra
2012-03-24 12:48     ` Peter Zijlstra
2012-03-24 12:48     ` Peter Zijlstra
2012-03-24 16:43     ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 16:43       ` Anton Vorontsov
2012-03-24 10:30 ` [PATCH 08/10] um: Fix possible race on task->mm Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 10:30   ` Anton Vorontsov
2012-03-24 11:12   ` Richard Weinberger [this message]
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 10:31 ` [PATCH 09/10] um: Properly check all process' threads for a live mm Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 11:12   ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 11:12     ` Richard Weinberger
2012-03-24 10:31 ` [PATCH 10/10] oom: Make find_lock_task_mm() sparse-aware Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 10:31   ` Anton Vorontsov
2012-03-24 12:52   ` Peter Zijlstra
2012-03-24 12:52     ` Peter Zijlstra
2012-03-24 12:52     ` Peter Zijlstra
2012-03-24 12:52     ` Peter Zijlstra
2012-03-24 12:52     ` Peter Zijlstra
2012-03-24 16:21     ` Anton Vorontsov
2012-03-24 16:21       ` Anton Vorontsov
2012-03-24 16:21       ` Anton Vorontsov
2012-03-24 16:21       ` Anton Vorontsov
2012-03-24 16:21       ` Anton Vorontsov
2012-03-24 16:43       ` Peter Zijlstra
2012-03-24 16:43         ` Peter Zijlstra
2012-03-24 16:43         ` Peter Zijlstra
2012-03-24 16:43         ` Peter Zijlstra
2012-03-24 16:43         ` Peter Zijlstra
2012-03-28  7:20     ` David Rientjes
2012-03-28  7:20       ` David Rientjes
2012-03-28  7:20       ` David Rientjes
2012-03-28  7:20       ` David Rientjes
2012-03-28  7:20       ` David Rientjes

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