From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757103Ab1FASFp (ORCPT ); Wed, 1 Jun 2011 14:05:45 -0400 Received: from casper.infradead.org ([85.118.1.10]:39445 "EHLO casper.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751516Ab1FASFo (ORCPT ); Wed, 1 Jun 2011 14:05:44 -0400 Subject: Re: [tip:sched/locking] sched: Add p->pi_lock to task_rq_lock() From: Peter Zijlstra To: Arne Jansen Cc: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, efault@gmx.de, npiggin@kernel.dk, akpm@linux-foundation.org, frank.rowand@am.sony.com, tglx@linutronix.de, mingo@elte.hu, linux-tip-commits@vger.kernel.org In-Reply-To: <4DE674EB.1000200@die-jansens.de> References: <20110405152729.232781355@chello.nl> <4DE64596.5010006@die-jansens.de> <1306946120.2497.606.camel@laptop> <4DE674EB.1000200@die-jansens.de> Content-Type: text/plain; charset="UTF-8" Date: Wed, 01 Jun 2011 20:09:11 +0200 Message-ID: <1306951751.2497.626.camel@laptop> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2011-06-01 at 19:20 +0200, Arne Jansen wrote: > On 01.06.2011 18:35, Peter Zijlstra wrote: > > On Wed, 2011-06-01 at 15:58 +0200, Arne Jansen wrote: > >> git bisect blames this commit for a problem I have with v3.0-rc1: > >> If I printk large amounts of data, the machine locks up. > >> As the commit does not revert cleanly on top of 3.0, I haven't been > >> able to double check. > >> The test I use is simple, just add something like > >> > >> for (i=0; i< 10000; ++i) printk("test %d\n", i); > >> > >> and trigger it, in most cases I can see the first 10 printks before > >> I have to power cycle the machine (sysrq-b does not work anymore). > >> Attached my .config. > > > > I've made me a module that does the above, I've also changed my .config > > to match yours (smp=y, sched-cgroup=y, autogroup=n, preempt=n, no_hz=y), > > but sadly I cannot reproduce, I get all 10k prints on my serial line. > > > > Even without serial line it works (somehow booting without visible > > console is scary as hell :) > > > > Which makes me ask, how are you observing your console? > > > > They don't go out to the serial line, I only observe them with a > tail -f on messages. Default log level doesn't go the console here. Right ok, so I used your exact .config, added a few drivers needed for my hardware and indeed, it doesn't even finish booting and gets stuck someplace. Sadly it looks like even the NMI watchdog is dead,.. /me goes try and make sense of this.