Subject: Re: [RFC][PATCH] Fix locking on misrouted interrupts
From: Ingo Molnar <mingo@redhat.com>
To: Pavel Emelianov <xemul@openvz.org>
Cc: Vivek Goyal <vgoyal@in.ibm.com>, Andrew Morton <akpm@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Kirill Korotaev <dev@sw.ru>
In-Reply-To: <4562BD4E.20600@openvz.org>
References: <4562BD4E.20600@openvz.org>
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Date: Tue, 21 Nov 2006 21:26:00 +0100
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On Tue, 2006-11-21 at 11:48 +0300, Pavel Emelianov wrote:
> Vivek noted that many places call note_interrupt()
> without desc->lock being held. Since note_interrupt()
> which tries to unlock this lock to handle spurious
> interrupts accodring to
> http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=f72fa707604c015a6625e80f269506032d5430dc
> 
> Looking at note_interrupt() I found that desc->lock
> IS required in this function but all the places that
> call note_interrupt() lock it after the call. One
> exception from this rule is __do_IRQ().
> 
> So I move spin_lock(&desc->lock); before calling
> note_interrupt() in all places.
> 
> Signed-off-bt: Pavel Emelianov <xemul@openvz.org>

indeed - and this is a fallout of the earlier fix in note_interrupt().
Andrew, Linus: i think this is a must-have for 2.6.19 as well.

Acked-by: Ingo Molnar <mingo@redhat.com>

	Ingo

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