From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [BUG] netconsole broken by scheduler updates Date: Thu, 26 May 2011 18:17:55 +0200 Message-ID: <1306426675.2497.84.camel@laptop> References: <4DDE1B7D.7080707@free.fr> <1306403308.1200.44.camel@twins> <4DDE7BEB.1050507@free.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: netdev@vger.kernel.org To: Laurent Riffard Return-path: Received: from casper.infradead.org ([85.118.1.10]:50380 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754017Ab1EZQOd (ORCPT ); Thu, 26 May 2011 12:14:33 -0400 Received: from j77219.upc-j.chello.nl ([24.132.77.219] helo=dyad.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.76 #1 (Red Hat Linux)) id 1QPdCx-00005o-1u for netdev@vger.kernel.org; Thu, 26 May 2011 16:14:47 +0000 In-Reply-To: <4DDE7BEB.1050507@free.fr> Sender: netdev-owner@vger.kernel.org List-ID: On Thu, 2011-05-26 at 18:12 +0200, Laurent Riffard wrote: > Le 26/05/2011 12:35, Laurent Riffard a =C3=A9crit : > > 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= hangs > >>> on boot near the network card initialization. I noticed that it d= oes > >>> hang just where a "inconsistent lock state" message normally appe= ars. > >>> > >>> I did a bisection : e4a52bcb9a18142d79e231b6733cabdbf2e67c1f is t= he > >>> 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 = does > >>> hang on boot, I have to push the reset button. > >> > >> Do you have CONFIG_HARDLOCKUP_DETECTOR=3Dy, and do you get an NMI = splat > >> after some 10 seconds? It would be interesting to see where its st= uck. > >=20 > > CONFIG_HARDLOCKUP_DETECTOR is not set for now. I'll give it a try. >=20 > 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. OK, thanks for trying, I shall try and reproduce locally.