From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ahmed S. Darwish" Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Date: Thu, 27 Jan 2011 05:33:47 +0200 Message-ID: <20110127033347.GA12477@laptop> References: <20110125134748.GA10051@laptop> <20110126124954.GC24527@laptop> <20110127021338.GA20334@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20110127021338.GA20334-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kexec-bounces-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org Errors-To: kexec-bounces+glkk-kexec=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Vivek Goyal Cc: Willy Tarreau , Dirk Hohndel , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , FBDEV-ML , IDE-ML , Randy Dunlap , James Bottomley , "H. Peter Anvin" , X86-ML , Ingo Molnar , Ingo Molnar , Jeff Garzik , Peter Zijlstra , Dirk.Hohndel-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, Borislav Petkov , Dave Jones , Thomas Gleixner , Mark Lord , Arjan van de Ven , Tony Luck , KEXEC-ML , LKML , Haren Myneni , Eric Biederman , Tejun List-Id: linux-ide@vger.kernel.org (Very timely! was just exploring kexec-tools and friends) On Wed, Jan 26, 2011 at 09:13:38PM -0500, Vivek Goyal wrote: > On Wed, Jan 26, 2011 at 02:49:54PM +0200, Ahmed S. Darwish wrote: > > > > If not, can kexec be modified to do so? That possibly needs the help > > of a a bootloader extension. > > - Generally kdump uses same kernel as first one. So if first kernel panics > then kdump kernel will also panic. Though one can keep a known good kdump > kernel. > I was thinking of a 'special' kdump kernel: the older kernel will just pass the physical RAM address of its ring buffer to the newer kernel. The newer kernel will be __so specialized__ that it will just: - display the log in a friendly manner - write it to the swap partition - .. and halt This way, I completely toss the BIOS while accomplishing similar goals. > > - Currently kexec-tools take care of loading the kdump kernel, and then > preparing memory map for second kernel and pass to it and also pass > along some information about vmcore in ELF headers to second kernel. > > There is so much to it that I really don't think that modifying bootloaders to > do all that might not trivial and more importantly I think it probably is not > worth the effort. > IMHO if done in a user-friendly and stable manner, it can really be worth the effort. But quite honestly, since I did not read all the setup work done by kexec-tools yet, I might be too optimistic. > Thanks > Vivek thanks, -- Darwish http://darwish.07.googlepages.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ww0-f49.google.com ([74.125.82.49]) by canuck.infradead.org with esmtps (Exim 4.72 #1 (Red Hat Linux)) id 1PiIcR-0006VH-Mu for kexec@lists.infradead.org; Thu, 27 Jan 2011 03:34:00 +0000 Received: by wwb17 with SMTP id 17so1727325wwb.18 for ; Wed, 26 Jan 2011 19:33:57 -0800 (PST) Date: Thu, 27 Jan 2011 05:33:47 +0200 From: "Ahmed S. Darwish" Subject: Re: [PATCH 0/2][concept RFC] x86: BIOS-save kernel log to disk upon panic Message-ID: <20110127033347.GA12477@laptop> References: <20110125134748.GA10051@laptop> <20110126124954.GC24527@laptop> <20110127021338.GA20334@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20110127021338.GA20334@redhat.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: Vivek Goyal Cc: Willy Tarreau , Dirk Hohndel , =?iso-8859-1?Q?Fr=E9d=E9ric?= Weisbecker , FBDEV-ML , IDE-ML , Randy Dunlap , James Bottomley , "H. Peter Anvin" , X86-ML , Ingo Molnar , Ingo Molnar , Jeff Garzik , Peter Zijlstra , Dirk.Hohndel@intel.com, Borislav Petkov , Dave Jones , Thomas Gleixner , Mark Lord , Arjan van de Ven , Tony Luck , KEXEC-ML , LKML , Haren Myneni , Eric Biederman , Tejun Heo , Andrew Morton , Linus Torvalds , Willy Tarreau (Very timely! was just exploring kexec-tools and friends) On Wed, Jan 26, 2011 at 09:13:38PM -0500, Vivek Goyal wrote: > On Wed, Jan 26, 2011 at 02:49:54PM +0200, Ahmed S. Darwish wrote: > > > > If not, can kexec be modified to do so? That possibly needs the help > > of a a bootloader extension. > > - Generally kdump uses same kernel as first one. So if first kernel panics > then kdump kernel will also panic. Though one can keep a known good kdump > kernel. > I was thinking of a 'special' kdump kernel: the older kernel will just pass the physical RAM address of its ring buffer to the newer kernel. The newer kernel will be __so specialized__ that it will just: - display the log in a friendly manner - write it to the swap partition - .. and halt This way, I completely toss the BIOS while accomplishing similar goals. > > - Currently kexec-tools take care of loading the kdump kernel, and then > preparing memory map for second kernel and pass to it and also pass > along some information about vmcore in ELF headers to second kernel. > > There is so much to it that I really don't think that modifying bootloaders to > do all that might not trivial and more importantly I think it probably is not > worth the effort. > IMHO if done in a user-friendly and stable manner, it can really be worth the effort. But quite honestly, since I did not read all the setup work done by kexec-tools yet, I might be too optimistic. > Thanks > Vivek thanks, -- Darwish http://darwish.07.googlepages.com _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec