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
Date: Wed, 8 Feb 2012 17:08:08 +0100 [thread overview]
Message-ID: <20120208160808.GB17177@redhat.com> (raw)
In-Reply-To: <20120207065004.GC1496@oksana.dev.rtsoft.ru>
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.
next prev parent reply other threads:[~2012-02-08 16:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-07 6:48 [PATCH 0/8] Fixes for common mistakes w/ for_each_process and task->mm Anton Vorontsov
2012-02-07 6:49 ` [PATCH 1/8] sysrq: Fix possible race with exiting task Anton Vorontsov
2012-02-09 1:47 ` David Rientjes
2012-02-07 6:49 ` [PATCH 2/8] sysrq: Properly check for kernel threads Anton Vorontsov
2012-02-09 1:46 ` David Rientjes
2012-02-07 6:50 ` [PATCH 3/8] arm: Fix possible race on task->mm Anton Vorontsov
2012-02-08 16:08 ` Oleg Nesterov [this message]
2012-02-09 15:33 ` Anton Vorontsov
2012-02-09 15:43 ` Anton Vorontsov
2012-02-10 20:21 ` Oleg Nesterov
2012-02-09 1:46 ` David Rientjes
2012-02-07 6:50 ` [PATCH 4/8] powerpc/mm: " Anton Vorontsov
2012-02-07 6:50 ` [PATCH 5/8] sh: " Anton Vorontsov
2012-02-07 6:50 ` [PATCH 6/8] blackfin: " Anton Vorontsov
2012-02-08 16:20 ` Oleg Nesterov
2012-02-07 6:51 ` [PATCH 7/8] um: Should hold tasklist_lock while traversing processes Anton Vorontsov
2012-02-07 6:51 ` [PATCH 8/8] um: Fix possible race on task->mm Anton Vorontsov
2012-02-08 15:59 ` [PATCH 0/8] Fixes for common mistakes w/ for_each_process and task->mm Oleg Nesterov
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