From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vivek Goyal Subject: Re: [PATCH 1/3] panic: Disable crash_kexec_post_notifiers if kdump is not available Date: Tue, 14 Jul 2015 10:20:04 -0400 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 Return-path: Content-Disposition: inline In-Reply-To: <20150714135919.GA18333-zu3NM2574RrQT0dZR+AlfA@public.gmane.org> Sender: linux-metag-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: dwalker-zu3NM2574RrQT0dZR+AlfA@public.gmane.org Cc: "Eric W. Biederman" , Hidehiro Kawai , Andrew Morton , linux-mips-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org, Baoquan He , linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-s390-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, kexec-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ingo Molnar , HATAYAMA Daisuke , Masami Hiramatsu , linuxppc-dev-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-metag-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org On Tue, Jul 14, 2015 at 01:59:19PM +0000, dwalker-zu3NM2574RrQT0dZR+AlfA@public.gmane.org wrote: > On Mon, Jul 13, 2015 at 08:19:45PM -0500, Eric W. Biederman wrote: > > dwalker-zu3NM2574RrQT0dZR+AlfA@public.gmane.org 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