Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754396Ab0BAGGT (ORCPT ); Mon, 1 Feb 2010 01:06:19 -0500 Received: from mail.windriver.com ([147.11.1.11]:43765 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754212Ab0BAGGS (ORCPT ); Mon, 1 Feb 2010 01:06:18 -0500 Message-ID: <4B666F41.9080302@windriver.com> Date: Mon, 01 Feb 2010 00:05:53 -0600 From: Jason Wessel User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Dongdong Deng CC: Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, kgdb-bugreport@lists.sourceforge.net, "Deng, Dongdong" , peterz@infradead.org Subject: Re: [PATCH 1/3] softlockup: add sched_clock_tick() to avoid kernel warning on kgdb resume References: <1264631124-4837-1-git-send-email-jason.wessel@windriver.com> <1264631124-4837-2-git-send-email-jason.wessel@windriver.com> <20100129080706.GJ14636@elte.hu> <4B62F5F6.3040401@windriver.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 01 Feb 2010 06:05:39.0916 (UTC) FILETIME=[9471C0C0:01CAA304] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1222 Lines: 35 Dongdong Deng wrote: > On Fri, Jan 29, 2010 at 10:51 PM, Jason Wessel > wrote: > >> echo 3 > /proc/sys/kernel/softlockup_thresh >> >> And then some kernel code in a thread like: >> local_irq_disable(); >> printk("Disable local irq for 11 seconds\n"); >> mdelay(11000); >> local_irq_enable(); >> > > Hi Jason, > > Maybe this problem was fixed by > commit baf48f6577e581a9adb8fe849dc80e24b21d171d - "softlock: fix false > panic which can occur if softlockup_thresh is reduced". > That is not the same problem. The fix you referenced is a corner case where you end up with the stack trace at the point in time you reduce the threshold. The only reason I reduce the threshold in the first place is just to shorten the amount of time it takes to observe the problem. You can just change the numbers for the mdelay and use the default softlockup threshold values and still see the problem I reported. Jason. -- 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/