From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Riffard Subject: Re: [BUG] netconsole broken by scheduler updates Date: Thu, 26 May 2011 18:12:27 +0200 Message-ID: <4DDE7BEB.1050507@free.fr> References: <4DDE1B7D.7080707@free.fr> <1306403308.1200.44.camel@twins> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Peter Zijlstra Return-path: Received: from smtp2-g21.free.fr ([212.27.42.2]:40354 "EHLO smtp2-g21.free.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751928Ab1EZQMg (ORCPT ); Thu, 26 May 2011 12:12:36 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Le 26/05/2011 12:35, Laurent Riffard a =E9crit : > On Thu, 26 May 2011, Peter Zijlstra wrote: >> On Thu, 2011-05-26 at 11:21 +0200, Laurent Riffard wrote: >>> Hi, >>> >>> Recently, netconsole was broken by some scheduler updates. Kernel h= angs >>> on boot near the network card initialization. I noticed that it doe= s >>> hang just where a "inconsistent lock state" message normally appear= s. >>> >>> I did a bisection : e4a52bcb9a18142d79e231b6733cabdbf2e67c1f is the >>> first bad commit. >>> commit e4a52bcb9a18142d79e231b6733cabdbf2e67c1f >>> Author: Peter Zijlstra >>> Date: Tue Apr 5 17:23:54 2011 +0200 >>> >>> sched: Remove rq->lock from the first half of ttwu() >>> >>> >>> Before this commit, kernel was booting succesfully despite the >>> "inconsistent lock state" message. After this commit, the kernel do= es >>> hang on boot, I have to push the reset button. >> >> Do you have CONFIG_HARDLOCKUP_DETECTOR=3Dy, and do you get an NMI sp= lat >> after some 10 seconds? It would be interesting to see where its stuc= k. >=20 > CONFIG_HARDLOCKUP_DETECTOR is not set for now. I'll give it a try. I activated CONFIG_HARDLOCKUP_DETECTOR, but failed to obtain more=20 information. During the boot, the kernel hangs just after bringing up=20 the NIC. I waited 2 minutes, without getting any more messages. ~~ laurent