From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jens Axboe Subject: Re: 4.4-rc3, KVM, br0 and instant hang Date: Sat, 5 Dec 2015 10:32:44 -0700 Message-ID: <56631FBC.4030002@fb.com> References: <22114.26609.457727.203801@quad.stoffel.home> <20151205162328.GA32532@quad.stoffel.home> <22115.8036.357755.548697@quad.stoffel.home> Mime-Version: 1.0 Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Cc: , , To: John Stoffel , John Stoffel Return-path: In-Reply-To: <22115.8036.357755.548697@quad.stoffel.home> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 12/05/2015 10:31 AM, John Stoffel wrote: >>>>>> "John" == John Stoffel writes: > > John> On Fri, Dec 04, 2015 at 11:28:33PM -0500, John Stoffel wrote: >>> >>> Hi all, > >>> Anyway, if I try to boot up anything past the 4.2.6 kernel, the system >>> locks up pretty quickly with an oops message that scrolls off the >>> screen too far. I've got some pictures which I'll attach in a bit, >>> maybe they'll help. So at first I thought it was something to do with >>> bad kworker threads, or SCSI or SATA interactions, but as I tried to >>> configure Netconsole to log to my beaglebone black SBC, I found out >>> that if I compiled and installed 4.4-rc3, started the bridge up (br0), >>> even started KVM, but did NOT start my VMs, the system was stable. > > I've now figured out that I can disable all my VMs from autostart, and > the system will come up properly. Then I can setup netconsole to use > the br0 interface, do an "echo t > sysrq" to confirm it's working, > and start up the VMs. > > On my most recent bootup, I thought it was ok, since the VMs worked > for a while (10 minutes) and I was starting to re-compile the kernel > again to make more modules compiled in. No luck, I got the following > crash dump (partial) on my netconsole box. > > [ 1434.266524] ------------[ cut here ]------------ > [ 1434.266643] WARNING: CPU: 2 PID: 179 at block/blk-merge.c:435 blk_rq_map_sg+0x2d9/0x2eb() This is fixed in current -git, as of a few days ago. -- Jens Axboe