From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754732Ab2AaPsB (ORCPT ); Tue, 31 Jan 2012 10:48:01 -0500 Received: from mx1.redhat.com ([209.132.183.28]:62570 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753804Ab2AaPsA (ORCPT ); Tue, 31 Jan 2012 10:48:00 -0500 Date: Tue, 31 Jan 2012 10:47:48 -0500 From: Don Zickus To: TAO HU Cc: linux-kernel@vger.kernel.org, Ingo Molnar Subject: Re: In many cases softlockup can not be reported after disabling IRQ for long time Message-ID: <20120131154748.GA5650@redhat.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 31, 2012 at 03:28:09PM +0800, TAO HU wrote: > Resend with a new subject > > On Wed, Jan 25, 2012 at 4:24 PM, TAO HU wrote: > > Hi, All > > > > While playing kernel 3.0.8 with below test code, it does NOT report > > any softlockup with 60%~70% chances. > > NOTE: the softlockup timeout is set to 10 seconds (i.e. > > watchdog_thresh=5) in my test. > > ... ... > > preempt_disable(); > > local_irq_disable(); > > for (i = 0; i < 20; i++) > >       mdelay(1000); > > local_irq_enable(); > > preempt_enable(); > > ... ... > > > > However, if I remove local_irq_disable()/local_irq_enable() it will > > report softlockup with no problem. > > I believe it is due to that after local_irq_enable() > > touch_softlockup_watchdog() is called prior softlockup timer. Hi Hu, Honestly, you should be getting hardlockup warnings if you are disabling interrupts. Do you see anything in the console output? Cheers, Don