From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from out02.mta.xmission.com ([166.70.13.232]) by merlin.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1UcNnK-0002OG-Ff for kexec@lists.infradead.org; Tue, 14 May 2013 22:34:07 +0000 From: ebiederm@xmission.com (Eric W. Biederman) References: <87k3n1w7a5.fsf@xmission.com> Date: Tue, 14 May 2013 15:33:29 -0700 In-Reply-To: (Dave Lloyd's message of "Tue, 14 May 2013 17:25:26 -0500") Message-ID: <87sj1pry2u.fsf@xmission.com> MIME-Version: 1.0 Subject: Re: Kernel panics when using kexec for rebooting 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" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: Dave Lloyd Cc: kexec@lists.infradead.org Dave Lloyd writes: > On Tue, May 14, 2013 at 5:01 PM, Eric W. Biederman > wrote: > >> >> Yes this does seem to be all over the place, and memory corruption >> probably caused by ongoing-dma seems like a reasonable hypothesis. > > Thank goodness it's not just me! :-) It is a classic issue, although I suspect something is unique in your setup because it has (to my knowledge) not been a widespread problem for years. >> The easy first thing to try is to remove all of your kernel modules >> before you reboot with kexec. Not infrequently the module remove path >> is better tested than the device shutdown path. > > I'm trying this now. In one panic, the pte referenced was > 0x100010000000000 which sure looks a whole like someone wrote his > registers in there. It certainly doesn't look like a valid pte. > > So far, unloading pata_acpi and pata_amd seem to have eliminated the > ACPI exception messages. I believe that this resets the device > properly. Unfortunately, it looks like lots of drivers don't implement > the pci_driver->shutdown call, so it would make sense that this is a > relatively widespread problem. Most devices don't leave dma setup if you reboot, and even more the generic pci clears the bus master DMA bit which shuts down a lot more dma. So the actual lack of a shutdown method is not as much of an issue as it might appear. Eric _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec