From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Date: Tue, 19 Jul 2011 14:54:11 -0400 From: Don Zickus Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to kexec path Message-ID: <20110719185411.GA3400@redhat.com> References: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64C3@USINDEVS01.corp.hds.com> <20110719183506.GA23770@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> 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: Seiji Aguchi Cc: Satoru Moriya , "dle-develop@lists.sourceforge.net" , "tony.luck@intel.com" , "hpa@zytor.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "Eric W. Biederman" , KOSAKI Motohiro , Jarod Wilson , Americo Wang , Andrew Morton , Vivek Goyal , Matthew Garrett On Tue, Jul 19, 2011 at 02:48:22PM -0400, Seiji Aguchi wrote: > >How is this safe? What happens if there's a pstore access in process > >when you hit this codepath? > > This will never happen because pstore_kmsg_dump_in_interrupt() is called after machine_crash_shutdown(). > > Panicked cpu sends NMI to all other cpus in machine_crash_shutdown() and they stop. > > > @@ -1081,6 +1083,7 @@ void crash_kexec(struct pt_regs *regs) > crash_setup_regs(&fixed_regs, regs); > crash_save_vmcoreinfo(); > machine_crash_shutdown(&fixed_regs); > + pstore_kmsg_dump_in_interrupt(KMSG_DUMP_KEXEC); > > Seiji Another interesting question is do we need to log anything in the kdump path? Isn't kdump generating the same info? What added value do we get over kdump? Cheers, Don _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 19 Jul 2011 14:54:11 -0400 From: Don Zickus To: Seiji Aguchi Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to kexec path Message-ID: <20110719185411.GA3400@redhat.com> References: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64C3@USINDEVS01.corp.hds.com> <20110719183506.GA23770@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> Cc: Satoru Moriya , "dle-develop@lists.sourceforge.net" , "tony.luck@intel.com" , "hpa@zytor.com" , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "Eric W. Biederman" , KOSAKI Motohiro , Jarod Wilson , Americo Wang , Andrew Morton , Vivek Goyal , Matthew Garrett List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, Jul 19, 2011 at 02:48:22PM -0400, Seiji Aguchi wrote: > >How is this safe? What happens if there's a pstore access in process > >when you hit this codepath? > > This will never happen because pstore_kmsg_dump_in_interrupt() is called after machine_crash_shutdown(). > > Panicked cpu sends NMI to all other cpus in machine_crash_shutdown() and they stop. > > > @@ -1081,6 +1083,7 @@ void crash_kexec(struct pt_regs *regs) > crash_setup_regs(&fixed_regs, regs); > crash_save_vmcoreinfo(); > machine_crash_shutdown(&fixed_regs); > + pstore_kmsg_dump_in_interrupt(KMSG_DUMP_KEXEC); > > Seiji Another interesting question is do we need to log anything in the kdump path? Isn't kdump generating the same info? What added value do we get over kdump? Cheers, Don From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751853Ab1GSSy3 (ORCPT ); Tue, 19 Jul 2011 14:54:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43903 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750933Ab1GSSy2 (ORCPT ); Tue, 19 Jul 2011 14:54:28 -0400 Date: Tue, 19 Jul 2011 14:54:11 -0400 From: Don Zickus To: Seiji Aguchi Cc: Matthew Garrett , "kexec@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-mtd@lists.infradead.org" , "Eric W. Biederman" , Vivek Goyal , KOSAKI Motohiro , Americo Wang , "tony.luck@intel.com" , Andrew Morton , Jarod Wilson , "hpa@zytor.com" , "dle-develop@lists.sourceforge.net" , Satoru Moriya Subject: Re: [RFC][PATCH -mmotm 1/4] Add static function calls of pstore to kexec path Message-ID: <20110719185411.GA3400@redhat.com> References: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64C3@USINDEVS01.corp.hds.com> <20110719183506.GA23770@srcf.ucam.org> <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5C4C569E8A4B9B42A84A977CF070A35B2C199C64D6@USINDEVS01.corp.hds.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 19, 2011 at 02:48:22PM -0400, Seiji Aguchi wrote: > >How is this safe? What happens if there's a pstore access in process > >when you hit this codepath? > > This will never happen because pstore_kmsg_dump_in_interrupt() is called after machine_crash_shutdown(). > > Panicked cpu sends NMI to all other cpus in machine_crash_shutdown() and they stop. > > > @@ -1081,6 +1083,7 @@ void crash_kexec(struct pt_regs *regs) > crash_setup_regs(&fixed_regs, regs); > crash_save_vmcoreinfo(); > machine_crash_shutdown(&fixed_regs); > + pstore_kmsg_dump_in_interrupt(KMSG_DUMP_KEXEC); > > Seiji Another interesting question is do we need to log anything in the kdump path? Isn't kdump generating the same info? What added value do we get over kdump? Cheers, Don