From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762101AbXEZQfe (ORCPT ); Sat, 26 May 2007 12:35:34 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753055AbXEZQf1 (ORCPT ); Sat, 26 May 2007 12:35:27 -0400 Received: from www.osadl.org ([213.239.205.134]:48243 "EHLO mail.tglx.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752783AbXEZQf1 (ORCPT ); Sat, 26 May 2007 12:35:27 -0400 Subject: Re: [2.6.21.1] soft lockup when removing netconsole module From: Thomas Gleixner To: Folkert van Heusden Cc: Parag Warudkar , linux-kernel@vger.kernel.org In-Reply-To: <20070526161645.GA11760@vanheusden.com> References: <20070526154011.GB3735@vanheusden.com> <465857DF.2020603@gmail.com> <1180195927.4264.11.camel@chaos> <20070526161645.GA11760@vanheusden.com> Content-Type: text/plain Date: Sat, 26 May 2007 18:35:24 +0200 Message-Id: <1180197324.4264.23.camel@chaos> Mime-Version: 1.0 X-Mailer: Evolution 2.8.3 (2.8.3-2.fc6) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 2007-05-26 at 18:17 +0200, Folkert van Heusden wrote: > > > Seems to be hrtimers related - CC'ed Thomas. > > I doubt that. The tick interrupt just finds out, that the machine is > > stuck in rmmod. > > > > Also the rmmod hangs and would not exit even with kill -9. It also > > > > sucks up 100% cpu. > > Can you please enable CONFIG_PROVE_LOCKING ? > > Luckily I already had :-) > Here is its output: So there is no output from lockdep, during the rmmod hang ? The rmmod sucks 100% cpu, so it busy loops at some place. Looking at the stack trace this seems to be in: void cancel_rearming_delayed_workqueue(struct workqueue_struct *wq, struct delayed_work *dwork) { while (!cancel_delayed_work(dwork)) flush_workqueue(wq); } which is not really related to timers :) tglx