Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756011AbXENOF1 (ORCPT ); Mon, 14 May 2007 10:05:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754439AbXENOFT (ORCPT ); Mon, 14 May 2007 10:05:19 -0400 Received: from mail.suse.de ([195.135.220.2]:53351 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753077AbXENOFR (ORCPT ); Mon, 14 May 2007 10:05:17 -0400 Date: Mon, 14 May 2007 16:05:15 +0200 From: Bernhard Walle To: Vivek Goyal Cc: Morton Andrew Morton , linux kernel mailing list Subject: Re: 2.6.21-rc7-mm2 "irqpoll" seems to be broken Message-ID: <20070514140513.GD29616@suse.de> Mail-Followup-To: Vivek Goyal , Morton Andrew Morton , linux kernel mailing list References: <20070426093620.GB2626@in.ibm.com> <20070426082405.67a0fdd2.akpm@linux-foundation.org> <20070430084833.GA16173@in.ibm.com> <20070502221932.GA488@suse.de> <20070508171841.GA29733@in.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070508171841.GA29733@in.ibm.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2114 Lines: 59 * Vivek Goyal [2007-05-08 19:18]: > On Thu, May 03, 2007 at 12:19:32AM +0200, Bernhard Walle wrote: > > * Vivek Goyal [2007-04-30 10:48]: > > > > > > handle_edge_irq() already makes sure that desc->action is not null, still > > > note_interrupt() is receiving desc->action as null, that's strange. On my > > > system this is happening for irq 4 and /proc/interrupt shows that it is > > > coming from "serial". > > > > Unfortunately, I couldn't reproduce this here. Vivek, do you have time > > to take a look at this at your site? For the meanwhile, should I > > create a patch that checks for desc->action in note_interrupt(), too? > > I can reproduce this problem only on one machine. I think there is some > race condition and your code somehow just exposes it. thanks for finding that out. Could you try/review out the patch below? As the lock is only aquired when irqfixup == 2 it shouldn't impact performance of a 'normal' system. Thanks, Bernhard --- kernel/irq/spurious.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-) --- a/kernel/irq/spurious.c +++ b/kernel/irq/spurious.c @@ -145,10 +145,20 @@ void note_interrupt(unsigned int irq, st } if (unlikely(irqfixup)) { - /* Don't punish working computers */ - if ((irqfixup == 2 && ((irq == 0) || - (desc->action->flags & IRQF_IRQPOLL))) || - action_ret == IRQ_NONE) { + int call_misrouted_irq = action_ret == IRQ_NONE; + + if (!call_misrouted_irq && irqfixup == 2) { + if (irq == 0) + call_misrouted_irq = 1; + else { + spin_lock(&desc->lock); + if (desc->action && (desc->action->flags & IRQF_IRQPOLL)) + call_misrouted_irq = 1; + spin_unlock(&desc->lock); + } + } + + if (call_misrouted_irq) { int ok = misrouted_irq(irq); if (action_ret == IRQ_NONE) desc->irqs_unhandled -= ok; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/