Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753755Ab2JRCQp (ORCPT ); Wed, 17 Oct 2012 22:16:45 -0400 Received: from mail-pa0-f46.google.com ([209.85.220.46]:56198 "EHLO mail-pa0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753707Ab2JRCQn (ORCPT ); Wed, 17 Oct 2012 22:16:43 -0400 MIME-Version: 1.0 In-Reply-To: <20120929071318.GA7444@gmail.com> References: <20120904143215.5bbbb2a4@obelix.rh> <20120923202727.GA28937@mwanda> <20120929071318.GA7444@gmail.com> Date: Thu, 18 Oct 2012 10:16:42 +0800 Message-ID: Subject: Re: kexec/kdump kernel fails to start From: Dave Young To: Ingo Molnar Cc: Yinghai Lu , Dan Carpenter , Cong Wang , Flavio Leitner , lkml , Ingo Molnar , Tejun Heo , ianfang.cn@gmail.com, Andrew Morton , Vivek Goyal Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3809 Lines: 106 On Sat, Sep 29, 2012 at 3:13 PM, Ingo Molnar wrote: > > * Yinghai Lu wrote: > >> On Sun, Sep 23, 2012 at 1:27 PM, Dan Carpenter wrote: >> > On Wed, Sep 05, 2012 at 11:34:25PM +0800, Cong Wang wrote: >> >> On Wed, Sep 5, 2012 at 1:32 AM, Flavio Leitner wrote: >> >> > Hi folks, >> >> > >> >> > I have system that no longer boots kdump kernel. Basically, >> >> > >> >> > # echo c > /proc/sysrq-trigger >> >> > >> >> > to dump a vmcore doesn't work. It just hangs after showing the usual >> >> > panic messages. I've bisected the problem and the commit introducing >> >> > the issue is the one below. >> >> > >> >> > Any idea? >> >> > >> >> > commit 722bc6b16771ed80871e1fd81c86d3627dda2ac8 >> >> > Author: WANG Cong 2012-03-05 20:05:13 >> >> > Committer: Ingo Molnar 2012-03-06 05:38:26 >> >> > Parent: 550cf00dbc8ee402bef71628cb71246493dd4500 (Merge tag 'mmc-fixes-for-3.3' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc) >> >> > Child: a6fca40f1d7f3e232c9de27c1cebbb9f787fbc4f (x86, tlb: Switch cr3 in leave_mm() only when needed) >> >> > Branches: master, remotes/origin/master >> >> > Follows: v3.3-rc6 >> >> > Precedes: v3.5-rc1 >> >> > >> >> > x86/mm: Fix the size calculation of mapping tables >> >> >> >> There was some attempt to fix this: >> >> https://patchwork.kernel.org/patch/1195751/ >> >> >> >> but for some reason it is not accepted. >> > >> > I filed a bug for this: >> > https://bugzilla.kernel.org/show_bug.cgi?id=47881 >> > >> > Is it fixed now? >> >> that offending patch should be reverted... >> >> 722bc6b16771ed80871e1fd81c86d3627dda2ac8 > > It does not revert cleanly - could someone send a (kexec > tested!) patch with a proper description? Hi, ingo Besides of commit 722bc6b16771ed80871e1fd81c86d3627dda2ac8, below commit also need revert. commit bd2753b2dda7bb43c7468826de75f49c6a7e8965 Author: Yinghai Lu Date: Wed Jun 6 10:55:40 2012 -0700 x86/mm: Only add extra pages count for the first memory range during pre-allocation early page table space Robin found this regression: | I just tried to boot an 8TB system. It fails very early in boot with: | Kernel panic - not syncing: Cannot find space for the kernel page tables git bisect commit 722bc6b16771ed80871e1fd81c86d3627dda2ac8. A git revert of that commit does boot past that point on the 8TB configuration. That commit will add up extra pages for all memory range even above 4g. Try to limit that extra page count adding to first entry only. Bisected-by: Robin Holt Tested-by: Robin Holt Signed-off-by: Yinghai Lu Cc: WANG Cong Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/CAE9FiQUj3wyzQxtq9yzBNc9u220p8JZ1FYHG7t%3DMOzJ%3D9BZMYA@mail.gmail.com Signed-off-by: Ingo Molnar OTOH, Jacob and Yinghai has better init_memory_mapping cleanup patches which are in tip:x86/mm2 already. Their patches fixes this issue as well. Since kdump does not work for long time since 722bc6b16771ed80871e1fd81c86d3627dda2ac8 Can you or someone else help to get the init_memory_mapping patches merged? Or do you still prefer to revert 722bc6b and bd2753b2d? I think stable kernel also need a fix. -- Regards Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/