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Date: Tue, 17 Nov 2009 00:04:42 +0100
From: Frederic Weisbecker <fweisbec@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: linux-kernel@vger.kernel.org, jeff@garzik.org, mingo@elte.hu,
       akpm@linux-foundation.org, jens.axboe@oracle.com, rusty@rustcorp.com.au,
       cl@linux-foundation.org, dhowells@redhat.com, arjan@linux.intel.com,
       torvalds@linux-foundation.org, avi@redhat.com, peterz@infradead.org,
       andi@firstfloor.org, Andi Kleen <ak@linux.intel.com>,
       Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH 01/21] workqueue: fix race condition in
	schedule_on_each_cpu()
Message-ID: <20091116230427.GD5293@nowhere>
References: <1258391726-30264-1-git-send-email-tj@kernel.org> <1258391726-30264-2-git-send-email-tj@kernel.org>
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On Tue, Nov 17, 2009 at 02:15:06AM +0900, Tejun Heo wrote:
> Commit 65a64464349883891e21e74af16c05d6e1eeb4e9 which allows
> schedule_on_each_cpu() to be called from keventd added a race
> condition.  schedule_on_each_cpu() may race with cpu hotplug and end
> up executing the function twice on a cpu.
> 
> Fix it by moving direct execution into the section protected with
> get/put_online_cpus().  While at it, update code such that direct
> execution is done after works have been scheduled for all other cpus
> and drop unnecessary cpu != orig test from flush loop.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Andi Kleen <ak@linux.intel.com>
> Cc: Oleg Nesterov <oleg@redhat.com>
> ---


Shouldn't this patch go to .32 ?
This looks like an important fix.

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