Date: Wed, 8 Feb 2012 17:08:08 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Greg KH <gregkh@linuxfoundation.org>,
        KOSAKI Motohiro <kosaki.motohiro@gmail.com>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Paul Mundt <lethal@linux-sh.org>,
        Russell King <linux@arm.linux.org.uk>,
        Mike Frysinger <vapier@gentoo.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Richard Weinberger <richard@nod.at>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] arm: Fix possible race on task->mm
Message-ID: <20120208160808.GB17177@redhat.com>
References: <20120207064809.GA29061@oksana.dev.rtsoft.ru> <20120207065004.GC1496@oksana.dev.rtsoft.ru>
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On 02/07, Anton Vorontsov wrote:
>
> 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,

Yes, but

> so let's take the task lock while we care about its mm.

it seems that this needs find_lock_task_mm() too ?

the same for the rest patches in this series.

Oleg.

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