From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753702AbYIESWd (ORCPT ); Fri, 5 Sep 2008 14:22:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751663AbYIESWZ (ORCPT ); Fri, 5 Sep 2008 14:22:25 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:57485 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751251AbYIESWY (ORCPT ); Fri, 5 Sep 2008 14:22:24 -0400 Date: Fri, 5 Sep 2008 11:22:21 -0700 From: Andrew Morton To: Marc Haber Cc: "linux-kernel@vger.kernel.org" Subject: Re: 2.6.26.3 mount process looping on ext3 rw remount Message-Id: <20080905112221.8be36263.akpm@linux-foundation.org> In-Reply-To: <20080905113901.GA2756@torres.zugschlus.de> References: <20080823084228.GA21293@torres.zugschlus.de> <20080825183528.30b66f45.akpm@linux-foundation.org> <20080905113901.GA2756@torres.zugschlus.de> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.12.5; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 5 Sep 2008 13:39:02 +0200 Marc Haber wrote: > On Mon, Aug 25, 2008 at 06:35:28PM -0700, Andrew Morton wrote: > > Please try to get a kernel profile while it's happening. oprofile > > maybe, or just the plain old timer-based profiler. There's some info > > in Documentation/basic_profiling.txt. > > I'll boot my next kernel with profile=2. > > > Actually, a simple alternative is to hit sysrq-P five or ten times. > > Most of the resulting stack traces will point back at where the CPU is > > stuck. > > Where are they written to? "P" in a sysrqd telnet session does not > result in anything being written to the kernel log or to dmesg. alt-sysrq-p from the attached keyboard. When operating remotely, use `echo p > /proc/sysrq-trigger'. The output will be in /var/log/messages and is accessible via `dmesg -s 1000000'. Please avoid email client wordwrapping when sending these logs. 99% of people do this and it makes the text very hard to read. > > This gets a bit hit-or-miss if you have multiple CPUs, because the > > sysrq-p trace can land on the wrong CPU. We recently added a sysrq-l > > which will generate a trace on all CPUS. > > "l" results in the SysRq HELP being written to the kernel log, so I > guess that "recently" means "not yet in 2.6.26.3". ok