From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from lo.gmane.org ([80.91.229.12]) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1QMWVJ-0005WH-T9 for kexec@lists.infradead.org; Wed, 18 May 2011 02:28:54 +0000 Received: from list by lo.gmane.org with local (Exim 4.69) (envelope-from ) id 1QMWVF-0006DJ-Q8 for kexec@lists.infradead.org; Wed, 18 May 2011 04:28:49 +0200 Received: from 60.247.97.98 ([60.247.97.98]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 18 May 2011 04:28:49 +0200 Received: from xiyou.wangcong by 60.247.97.98 with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Wed, 18 May 2011 04:28:49 +0200 From: WANG Cong Subject: Re: kdump with /proc/oldproc Date: Wed, 18 May 2011 02:28:38 +0000 (UTC) Message-ID: References: Mime-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: kexec@lists.infradead.org On Tue, 17 May 2011 12:30:58 -0500, Nathan D Miller wrote: > Hello- > > Has anyone tried reconstituting a portion of the old kernel's /proc > while in the capture kernel? > > I had the idea while digging through the kexec/kdump code and it seemed > intriguing. > > It might be a means by which user-space dump applications running under > the capture kernel could interrogate the old system, and identify bad > processes that instigated the panic. In particular, I'm thinking of Out > Of Memory scenarios. We've modified our kernel to panic instead of > invoking the kernel's OOM killer, but we still have the problem of > identifying the "bad" process while running in the capture kernel. > > Perhaps everything could be accomplished using some sort of FUSE > file-system around /proc/oldmem and /proc/vmcore. Not all the > proc// files would need to be implemented, of course. In addition, > each old process could have its own 'vmcore' file for getting a core > dump of the original process. > Well, actually you don't need to bother the old /proc to find which process is the killer. The old dmesg contains the PID/comm of the killer process, and we have a tool named vmcore-dmesg to read out the dmesg from the vmcore. With the utility 'crash', you can query any info of any process in the old kernel, so why do you need a per-process vmcore anyway? Thanks. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec