From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from stargate.chelsio.com ([12.32.117.8]:62857 "EHLO stargate.chelsio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750954AbeC0P2Y (ORCPT ); Tue, 27 Mar 2018 11:28:24 -0400 Date: Tue, 27 Mar 2018 20:57:16 +0530 From: Rahul Lakkireddy To: "Eric W. Biederman" Cc: "netdev@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "davem@davemloft.net" , "viro@zeniv.linux.org.uk" , "stephen@networkplumber.org" , "akpm@linux-foundation.org" , "torvalds@linux-foundation.org" , Ganesh GR , Nirranjan Kirubaharan , Indranil Choudhury Subject: Re: [PATCH net-next v2 0/2] kernel: add support to collect hardware logs in crash recovery kernel Message-ID: <20180327152715.GA18097@chelsio.com> References: <87muyxlctn.fsf@xmission.com> <20180326134539.GA15852@chelsio.com> <87k1txfyj5.fsf@xmission.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87k1txfyj5.fsf@xmission.com> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On Tuesday, March 03/27/18, 2018 at 18:47:34 +0530, Eric W. Biederman wrote: > Rahul Lakkireddy writes: > > > On Saturday, March 03/24/18, 2018 at 20:50:52 +0530, Eric W. Biederman wrote: > >> > >> Rahul Lakkireddy writes: > >> > >> > On production servers running variety of workloads over time, kernel > >> > panic can happen sporadically after days or even months. It is > >> > important to collect as much debug logs as possible to root cause > >> > and fix the problem, that may not be easy to reproduce. Snapshot of > >> > underlying hardware/firmware state (like register dump, firmware > >> > logs, adapter memory, etc.), at the time of kernel panic will be very > >> > helpful while debugging the culprit device driver. > >> > > >> > This series of patches add new generic framework that enable device > >> > drivers to collect device specific snapshot of the hardware/firmware > >> > state of the underlying device in the crash recovery kernel. In crash > >> > recovery kernel, the collected logs are exposed via /sys/kernel/crashdd/ > >> > directory, which is copied by user space scripts for post-analysis. > >> > > >> > A kernel module crashdd is newly added. In crash recovery kernel, > >> > crashdd exposes /sys/kernel/crashdd/ directory containing device > >> > specific hardware/firmware logs. > >> > >> Have you looked at instead of adding a sysfs file adding the dumps > >> as additional elf notes in /proc/vmcore? > >> > > > > I see the crash recovery kernel's memory is not present in any of the > > the PT_LOAD headers. So, makedumpfile is not collecting the dumps > > that are in crash recovery kernel's memory. > > > > Also, are you suggesting exporting the dumps themselves as PT_NOTE > > instead? I'll look into doing it this way. > > Yes. I was suggesting exporting the dumps themselves as PT_NOTE > in /proc/vmcore. I think that will allow makedumpfile to collect > your new information without modification. > If I export the dumps themselves as PT_NOTE in /proc/vmcore, can the crash tool work without modification; i.e can crash tool extract these notes? Thanks, Rahul