From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 14 Jul 2015 16:20:10 +0200 (CEST) Received: from mx1.redhat.com ([209.132.183.28]:42374 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S27009828AbbGNOUIvS61u (ORCPT ); Tue, 14 Jul 2015 16:20:08 +0200 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (Postfix) with ESMTPS id 06FA6BBB30; Tue, 14 Jul 2015 14:20:04 +0000 (UTC) Received: from horse.redhat.com (dhcp-25-235.bos.redhat.com [10.18.25.235]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id t6EEK4pX007140; Tue, 14 Jul 2015 10:20:04 -0400 Received: by horse.redhat.com (Postfix, from userid 10451) id 14F4020220E; Tue, 14 Jul 2015 10:20:04 -0400 (EDT) Date: Tue, 14 Jul 2015 10:20:04 -0400 From: Vivek Goyal To: dwalker@fifo99.com Cc: "Eric W. Biederman" , Hidehiro Kawai , Andrew Morton , linux-mips@linux-mips.org, Baoquan He , linux-sh@vger.kernel.org, linux-s390@vger.kernel.org, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, Ingo Molnar , HATAYAMA Daisuke , Masami Hiramatsu , linuxppc-dev@lists.ozlabs.org, linux-metag@vger.kernel.org, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 1/3] panic: Disable crash_kexec_post_notifiers if kdump is not available Message-ID: <20150714142004.GB10792@redhat.com> References: <20150710113331.4368.10495.stgit@softrs> <20150710113331.4368.63745.stgit@softrs> <87wpy82kqf.fsf@x220.int.ebiederm.org> <20150713202611.GA16525@fifo99.com> <87h9p7r0we.fsf@x220.int.ebiederm.org> <20150714135919.GA18333@fifo99.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150714135919.GA18333@fifo99.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Scanned-By: MIMEDefang 2.68 on 10.5.11.27 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 48275 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: vgoyal@redhat.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips On Tue, Jul 14, 2015 at 01:59:19PM +0000, dwalker@fifo99.com wrote: > On Mon, Jul 13, 2015 at 08:19:45PM -0500, Eric W. Biederman wrote: > > dwalker@fifo99.com writes: > > > > > On Fri, Jul 10, 2015 at 08:41:28AM -0500, Eric W. Biederman wrote: > > >> Hidehiro Kawai writes: > > >> > > >> > You can call panic notifiers and kmsg dumpers before kdump by > > >> > specifying "crash_kexec_post_notifiers" as a boot parameter. > > >> > However, it doesn't make sense if kdump is not available. In that > > >> > case, disable "crash_kexec_post_notifiers" boot parameter so that > > >> > you can't change the value of the parameter. > > >> > > >> Nacked-by: "Eric W. Biederman" > > > > > > I think it would make sense if he just replaced "kdump" with "kexec". > > > > It would be less insane, however it still makes no sense as without > > kexec on panic support crash_kexec is a noop. So the value of the > > seeting makes no difference. > > Can you explain more, I don't really understand what you mean. Are you suggesting > the whole "crash_kexec_post_notifiers" feature has no value ? If CONFIG_KEXEC=n, then crash_kexec() is a nop. So it does not matter whether crash_kexec() is called before panic notifiers or after. IOW, what do you gain by disabling crash_kexec_post_notifiers, in case of CONFIG_KEXEC=n? Thanks Vivek