From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757988Ab1K3RP7 (ORCPT ); Wed, 30 Nov 2011 12:15:59 -0500 Received: from e24smtp04.br.ibm.com ([32.104.18.25]:56961 "EHLO e24smtp04.br.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757888Ab1K3RP5 (ORCPT ); Wed, 30 Nov 2011 12:15:57 -0500 Date: Wed, 30 Nov 2011 22:45:24 +0530 From: "K.Prasad" To: Vivek Goyal Cc: linux-kernel@vger.kernel.org, Borislav Petkov , "Luck, Tony" , "Eric W. Biederman" , anderson@redhat.com, tachibana@mxm.nes.nec.co.jp, oomichi@mxs.nes.nec.co.jp, Valdis.Kletnieks@vt.edu, Nick Bowler Subject: Re: [RFC Patch 0/2] Slimdump framework using CRASH_REASON - v2 Message-ID: <20111130171524.GA2632@in.ibm.com> Reply-To: prasad@linux.vnet.ibm.com References: <20111121095405.GA2289@in.ibm.com> <20111121151727.GF313@redhat.com> <20111123173318.GB2515@in.ibm.com> <20111128142402.GA20758@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111128142402.GA20758@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) x-cbid: 11113017-8936-0000-0000-0000053A875A Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 28, 2011 at 09:24:02AM -0500, Vivek Goyal wrote: > On Wed, Nov 23, 2011 at 11:03:18PM +0530, K.Prasad wrote: > > On Mon, Nov 21, 2011 at 10:17:27AM -0500, Vivek Goyal wrote: > > > On Mon, Nov 21, 2011 at 03:24:05PM +0530, K.Prasad wrote: [snipped] > > > > The kernel message buffers can be obtained by using the --dump-dmesg > > option of makedumpfile but again that's risky. We wouldn't know if it'll > > cause access to the faulty memory (which is how the previous method of having > > a new elf-notes in a pristine location is much safer). > > > > The method in this patch is quite primitive in that informs the user > > nothing more than a one-line cause of crash. One should take help from other > > tools (such as service processor/firmware/ACPI logs, or previous corrected > > error logs) to infer the location of bad memory. > > And how does one get to firmware/ACPI logs? Many system don't have service > processor also. > > I think extracting kernel buffers by default in case of MCE is reasonable. > This should allow somebody to figure out some MCE related information. > > You might want to modify makedumpfile so that it does not try to access > pages marked poisoned. > I'm not sure how easy or difficult it would be to skip hw-poisoned pages from user-space i.e. makedumpfile. I'll start working on the relevant changes though, and keep the community posted with the patches. Thanks, K.Prasad