From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [2/3] 2.6.22-rc2: known regressions v2 Date: Fri, 25 May 2007 09:33:54 -0700 Message-ID: <20070525093354.5dbe5f43.akpm@linux-foundation.org> References: <46558708.2040803@googlemail.com> <46559B54.80106@googlemail.com> <20070524193740.GA6787@elte.hu> <20070525101105.GA9268@elte.hu> <4656CE39.8050800@netunix.com> <20070525123456.GA17238@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20070525123456.GA17238@elte.hu> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: linux-pm-bounces@lists.linux-foundation.org Errors-To: linux-pm-bounces@lists.linux-foundation.org To: Ingo Molnar Cc: "Cherwin R. Nooitmeer" , Kristian H?gsberg , Mikael Pettersson , Pavel Machek , sparclinux@vger.kernel.org, linux1394-devel@lists.sourceforge.net, Andrey@smtp2.linux-foundation.org, linux-usb-devel@lists.sourceforge.net, Alan Cox , linux-pm@lists.linux-foundation.org, Christoph Lameter , Robert de Rooy , Tejun Heo , Michal Piotrowski , linux-pcmcia@lists.infradead.org, Marcus Better , Greg@smtp2.linux-foundation.org, Kroah-Hartman , LKML , Stefan Richter , Chris Newport List-Id: linux-pm@vger.kernel.org On Fri, 25 May 2007 14:34:56 +0200 Ingo Molnar wrote: > * Chris Newport wrote: > > > There is a fundamental problem in getting a decent log to debug a > > crashed kernel. Maybe we should take a hint from Solaris. If the > > kernel crashes Solaris dumps core to swap and sets a flag. At the next > > boot this image is copied to /var/adm/crashdump where it is preserved > > for future debugging. Obviously swap needs to be larger than core, but > > this is usually the case. > > we've got kdump, but it's not usually enabled by default by distros. Isn't that awful? By now we should be in the situation where if a tester is hitting a kernel crash we can say to them "please turn on crashdumps and send me the image". But we're not - kernel developers don't know how to turn the thing on in $RANDOM_DISTRO, testers have no experience with the feature and kernel developers don't have experience handling the crash images. And I'm not sure that the (required) "don't dump user memory and pagecache" feature has been implemented yet? It'd be in our interests to push all this along a bit. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Date: Fri, 25 May 2007 16:33:54 +0000 Subject: Re: [2/3] 2.6.22-rc2: known regressions v2 Message-Id: <20070525093354.5dbe5f43.akpm@linux-foundation.org> List-Id: References: <46558708.2040803@googlemail.com> <46559B54.80106@googlemail.com> <20070524193740.GA6787@elte.hu> <20070525101105.GA9268@elte.hu> <4656CE39.8050800@netunix.com> <20070525123456.GA17238@elte.hu> In-Reply-To: <20070525123456.GA17238@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Ingo Molnar Cc: "Cherwin R. Nooitmeer" , Kristian H?gsberg , Mikael Pettersson , Pavel Machek , sparclinux@vger.kernel.org, linux1394-devel@lists.sourceforge.net, Andrey@smtp2.linux-foundation.org, linux-usb-devel@lists.sourceforge.net, Alan Cox , linux-pm@lists.linux-foundation.org, Christoph Lameter , Robert de Rooy , Tejun Heo , Michal Piotrowski , linux-pcmcia@lists.infradead.org, Marcus Better , Greg@smtp2.linux-foundation.org, Kroah-Hartman , LKML , Stefan Richter , Chris Newport On Fri, 25 May 2007 14:34:56 +0200 Ingo Molnar wrote: > * Chris Newport wrote: > > > There is a fundamental problem in getting a decent log to debug a > > crashed kernel. Maybe we should take a hint from Solaris. If the > > kernel crashes Solaris dumps core to swap and sets a flag. At the next > > boot this image is copied to /var/adm/crashdump where it is preserved > > for future debugging. Obviously swap needs to be larger than core, but > > this is usually the case. > > we've got kdump, but it's not usually enabled by default by distros. Isn't that awful? By now we should be in the situation where if a tester is hitting a kernel crash we can say to them "please turn on crashdumps and send me the image". But we're not - kernel developers don't know how to turn the thing on in $RANDOM_DISTRO, testers have no experience with the feature and kernel developers don't have experience handling the crash images. And I'm not sure that the (required) "don't dump user memory and pagecache" feature has been implemented yet? It'd be in our interests to push all this along a bit. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763734AbXEYQf3 (ORCPT ); Fri, 25 May 2007 12:35:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752107AbXEYQfW (ORCPT ); Fri, 25 May 2007 12:35:22 -0400 Received: from smtp1.linux-foundation.org ([207.189.120.13]:60048 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760790AbXEYQfU (ORCPT ); Fri, 25 May 2007 12:35:20 -0400 Date: Fri, 25 May 2007 09:33:54 -0700 From: Andrew Morton To: Ingo Molnar Cc: Chris Newport , Linus Torvalds , Christoph Lameter , Michal Piotrowski , LKML , "Cherwin R. Nooitmeer" , linux-pcmcia@lists.infradead.org, Robert de Rooy , Alan Cox , Tejun Heo , sparclinux@vger.kernel.org, David Miller , Mikael Pettersson , linux1394-devel@lists.sourceforge.net, Stefan Richter , Kristian H?gsberg , linux-pm@lists.linux-foundation.org, "Rafael J. Wysocki" , Pavel Machek , Marcus Better , Andrey Borzenkov , linux-usb-devel@lists.sourceforge.net, Greg Kroah-Hartman Subject: Re: [2/3] 2.6.22-rc2: known regressions v2 Message-Id: <20070525093354.5dbe5f43.akpm@linux-foundation.org> In-Reply-To: <20070525123456.GA17238@elte.hu> References: <46558708.2040803@googlemail.com> <46559B54.80106@googlemail.com> <20070524193740.GA6787@elte.hu> <20070525101105.GA9268@elte.hu> <4656CE39.8050800@netunix.com> <20070525123456.GA17238@elte.hu> X-Mailer: Sylpheed 2.4.1 (GTK+ 2.8.17; x86_64-unknown-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 25 May 2007 14:34:56 +0200 Ingo Molnar wrote: > * Chris Newport wrote: > > > There is a fundamental problem in getting a decent log to debug a > > crashed kernel. Maybe we should take a hint from Solaris. If the > > kernel crashes Solaris dumps core to swap and sets a flag. At the next > > boot this image is copied to /var/adm/crashdump where it is preserved > > for future debugging. Obviously swap needs to be larger than core, but > > this is usually the case. > > we've got kdump, but it's not usually enabled by default by distros. Isn't that awful? By now we should be in the situation where if a tester is hitting a kernel crash we can say to them "please turn on crashdumps and send me the image". But we're not - kernel developers don't know how to turn the thing on in $RANDOM_DISTRO, testers have no experience with the feature and kernel developers don't have experience handling the crash images. And I'm not sure that the (required) "don't dump user memory and pagecache" feature has been implemented yet? It'd be in our interests to push all this along a bit.