From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail2.vodafone.ie ([213.233.128.44]) by canuck.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1RJXlD-0007ES-H4 for kexec@lists.infradead.org; Thu, 27 Oct 2011 21:45:16 +0000 Message-ID: <4EA9D09E.800@draigBrady.com> Date: Thu, 27 Oct 2011 22:43:58 +0100 From: =?ISO-8859-1?Q?P=E1draig_Brady?= MIME-Version: 1.0 Subject: Re: watchdogs and kdump References: <20111027203029.GR3452@redhat.com> In-Reply-To: <20111027203029.GR3452@redhat.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: kexec-bounces@lists.infradead.org Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Don Zickus Cc: kexec@lists.infradead.org, linux-watchdog@vger.kernel.org, vgoyal@redhat.com, amwang@redhat.com On 10/27/2011 09:30 PM, Don Zickus wrote: > Hi, > = > I was assisting a customer the other day debugging a kdump[1] problem, wh= en we > noticed the real problem was the hardware watchdog was firing and > rebooting the box. > = > Of course, this can be inconvienant if the panic happens right before the > watchdog is supposed to be kicked, leading to a spontaneous reboot before > the second kernel finishes booting and loading the watchdog module. > = > I was trying to think of a way to solve this and thought, one way to > minimize the problem is to kick the watchdog before we jump into the kdump > kernel. Another way is to disable the watchdog entirely, but that doesn't > work on all hardware I believe. > = > Anyway, I was posting on the watchdog mailing list to see if anyone had a= ny > ideas that might help. And if my above idea to kick the watchdog before > jumping into the kdump kernel seems ok, then an api would need to be > developed. > = > I am willing to do any coding and testing necessary, but before I did, I > wanted help to get a direction to go in first. > = > Thoughts? Seems like the appropriate thing to do is to call all the reboot notifiers that each watchdog registers. Since one is not doingn a full SYS_RESTART (SYS_DOWN) though, i.e. not running through the BIOS code again, it might be worth having a different SYS_JUMP code in notifier.h that would allow you to kick rather than stop the watchdogs as the reboot notifiers generally do at the moment. I think it would be important not to stop the watchdog if possible, given the large amount of logic that's going to be executed after the jump. cheers, P=E1draig. _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec