Message-ID: <4562B476.801@sw.ru>
Date: Tue, 21 Nov 2006 11:10:30 +0300
From: Pavel Emelianov <xemul@sw.ru>
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To: vgoyal@in.ibm.com, mingo@redhat.com
CC: Andrew Morton <akpm@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
       Kirill Korotaev <dev@openvz.org>
Subject: Re: [RFC] [PATCH] Fix misrouted interrupts deadlocks
References: <455484E4.1020100@openvz.org> <20061120192335.GA11879@in.ibm.com> <20061120195652.GA6141@in.ibm.com>
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> Hi Pavel,
> 
> If I backout your changes, everything works fine. So it looks like that
> the problem I am facing is because of your patch but I don't have a logical
> explanation yet that why the problem is there. Just realasing a lock
> which is not currently acquired should not hang the system?


Hm... A simple grep over the code showed that note_interrupt
is called w/o desc->lock in all places but __do_IRQ(). And this
looks like an error at least for the following reason:
note_interrupt() calls __report_bad_irq() and __report_bad_irq()
does require desc->lock to be held. So I suppose that we have
to do spin_lock(&desc->lock) before calling note_interrupt().
I'll prepare a patch in a moment.
-
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