From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754769Ab0DBVJc (ORCPT ); Fri, 2 Apr 2010 17:09:32 -0400 Received: from ksp.mff.cuni.cz ([195.113.26.206]:59306 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754551Ab0DBVJZ (ORCPT ); Fri, 2 Apr 2010 17:09:25 -0400 Date: Fri, 2 Apr 2010 23:09:17 +0200 From: Pavel Machek To: Thomas Gleixner Cc: Andi Kleen , Linus Torvalds , LKML , linux-arch@vger.kernel.org, Andrew Morton , Ingo Molnar , Peter Zijlstra , Alan Cox , David Miller , Greg Kroah-Hartman , Arnaldo Carvalho de Melo Subject: Re: [patch 1/2] genirq: Run irq handlers with interrupts disabled Message-ID: <20100402210916.GA23339@elf.ucw.cz> References: <20100326000325.917127328@linutronix.de> <20100326000405.758579387@linutronix.de> <20100326061310.GV20695@one.firstfloor.org> <20100330053325.GL20695@one.firstfloor.org> <20100402093132.GA1360@ucw.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri 2010-04-02 22:42:51, Thomas Gleixner wrote: > On Fri, 2 Apr 2010, Pavel Machek wrote: > > > On Wed 2010-03-31 13:16:37, Thomas Gleixner wrote: > > > On Tue, 30 Mar 2010, Andi Kleen wrote: > > > > > > > > Why not simply force IRQF_DISABLED for all MSI interrupts. That still > > > > > allows nesting for non MSI ones, but it limits the chance of throwing > > > > > up reasonably well. That's a two liner. > > > > > > > > > > Can you please test whether it resolves the issue at hand ? > > > > > > > > Sorry for the late answer. Got confirmation that this patch > > > > fixes the test case. Thanks. > > > > > > Ok, I'll push it linus wards and cc stable. I think thats the least > > > intrusive safe bet we can have right now. > > > > stable? I'd say thats way too intrusive for -stable... > > So we better let the possible stack overruns unaddressed ? -stable should have no regressions, first and foremost. And this is pretty certain to introduce some, at least on low-powered system with serial ports. So yes, it is probably better to let the possible stack overruns unaddressed. We have lived with them for 15 years or so... (Alternatively, just make the irq stacks bigger? Or just take Andi's patch, which solves the overruns, and only introduces latency regressions when it would otherwise crash?) Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html