From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756604AbYDWLWS (ORCPT ); Wed, 23 Apr 2008 07:22:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750973AbYDWLWE (ORCPT ); Wed, 23 Apr 2008 07:22:04 -0400 Received: from viefep18-int.chello.at ([213.46.255.22]:41887 "EHLO viefep16-int.chello.at" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750995AbYDWLWC (ORCPT ); Wed, 23 Apr 2008 07:22:02 -0400 X-SourceIP: 80.56.237.116 Subject: Re: [git pull] scheduler changes for v2.6.26 From: Peter Zijlstra To: Mike Galbraith Cc: Ingo Molnar , Frans Pop , torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, Richard Jonsson , "Rafael J. Wysocki" In-Reply-To: <1208946604.4803.9.camel@marge.simson.net> References: <20080419181304.GB21353@elte.hu> <200804192147.43719.elendil@planet.nl> <20080421123903.GE9554@elte.hu> <200804211831.29976.elendil@planet.nl> <20080421194359.GD8770@elte.hu> <1208854300.4695.7.camel@marge.simson.net> <20080422085905.GA9939@elte.hu> <1208867154.4873.4.camel@marge.simson.net> <1208938303.4905.23.camel@marge.simson.net> <1208946604.4803.9.camel@marge.simson.net> Content-Type: text/plain Date: Wed, 23 Apr 2008 13:21:55 +0200 Message-Id: <1208949715.7115.334.camel@twins> Mime-Version: 1.0 X-Mailer: Evolution 2.22.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2008-04-23 at 12:30 +0200, Mike Galbraith wrote: > On Wed, 2008-04-23 at 10:11 +0200, Mike Galbraith wrote: > > > I dug my old p3/500 out and hooked it up since I still can't get minicom > > functional plugging P4->Q6600, but no joy. Whatever the heck is going > > wrong in sched-devel is so catastrophic that not one character hits the > > console when it locks, and nmi_watchdog=1 does nada. > > I built x86/latest to see if it locked, and while testing to see if > minicom was really really working properly on p3/500, I created an > explosion. I see in the log that clockevents griped during boot, and > when I later poked SysRq-W, box blew to pieces. > [ 604.923629] BUG: unable to handle kernel NULL pointer dereference at 0000000000000018 > [ 604.923629] IP: [] seq_printf+0x2e/0xa7 Sorry about that :-/ this should fix it: --- Subject: sched: fix oops sched_debug uses SEQ_printf to use printk when the seqfile 'm' is NULL. Instead of doing that here too; choose to not output the weight tree to cut back on output. Signed-off-by: Peter Zijlstra --- diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 89fa32b..353a481 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1643,8 +1643,10 @@ static void print_cfs_stats(struct seq_file *m, int cpu) for_each_leaf_cfs_rq(cpu_rq(cpu), cfs_rq) print_cfs_rq(m, cpu, cfs_rq); - seq_printf(m, "\nWeight tree:\n"); - print_cfs_rq_tasks(m, &cpu_rq(cpu)->cfs, 1); + if (m) { + seq_printf(m, "\nWeight tree:\n"); + print_cfs_rq_tasks(m, &cpu_rq(cpu)->cfs, 1); + } rcu_read_unlock(); } #endif