From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751258AbWFSRuq (ORCPT ); Mon, 19 Jun 2006 13:50:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751267AbWFSRuq (ORCPT ); Mon, 19 Jun 2006 13:50:46 -0400 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:1219 "EHLO ebiederm.dsl.xmission.com") by vger.kernel.org with ESMTP id S1751258AbWFSRup (ORCPT ); Mon, 19 Jun 2006 13:50:45 -0400 From: ebiederm@xmission.com (Eric W. Biederman) To: vgoyal@in.ibm.com Cc: Preben Traerup , fastboot@lists.osdl.org, linux-kernel@vger.kernel.org Subject: Re: [Fastboot] [PATCH] kdump: add a missing notifier before crashing References: <20060615201621.6e67d149.akiyama.nobuyuk@jp.fujitsu.com> <20060616211555.1e5c4af0.akiyama.nobuyuk@jp.fujitsu.com> <20060619163053.f0f10a5e.akiyama.nobuyuk@jp.fujitsu.com> <4496A677.3020301@ericsson.com> <20060619170711.GB8172@in.ibm.com> Date: Mon, 19 Jun 2006 11:50:24 -0600 In-Reply-To: <20060619170711.GB8172@in.ibm.com> (Vivek Goyal's message of "Mon, 19 Jun 2006 13:07:11 -0400") Message-ID: User-Agent: Gnus/5.110004 (No Gnus v0.4) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Vivek Goyal writes: > On Mon, Jun 19, 2006 at 10:49:32AM -0600, Eric W. Biederman wrote: > > Sounds like trouble for modules. I am assuming that code to power down the > scsi disks/controller will be part of the driver, which is generally built > as a module and also assuming that powering down the disks is a valid > requirement after the crash. I'm assuming if anything is important and critical enough to be in a crash notifier it can be built into the kernel. > After introducing an option to disable/enable crash notifiers from user > space I think now responsibility lies to with user. If he chooses to enable > the notifiers, he understands that there are chances that we never boot > into the next kernel and get lost in between. At the moment this is a lot of infrastructure for a vaguely defined case that I have yet to see defined. One of the reasons using kexec for this kind of activity was precisely because it doesn't do any of this when the kernel is known to be broken. Having notifiers and being able to disable them is designing for an unspecified case. We need to concentrate on the fundamentals here. Do any of these crash notifiers make sense? If after the notifiers are well understood they it makes sense to add a general framework etc, then I'm for it. Eric