From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36424) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gIend-0000jC-Ut for qemu-devel@nongnu.org; Fri, 02 Nov 2018 15:08:06 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gIenX-000896-5a for qemu-devel@nongnu.org; Fri, 02 Nov 2018 15:08:03 -0400 Received: from mail.windriver.com ([147.11.1.11]:44827) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gIenW-000800-Od for qemu-devel@nongnu.org; Fri, 02 Nov 2018 15:07:58 -0400 References: <87pnvn6hnq.fsf@linaro.org> From: Chris Friesen Message-ID: Date: Fri, 2 Nov 2018 09:31:19 -0600 MIME-Version: 1.0 In-Reply-To: <87pnvn6hnq.fsf@linaro.org> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] strange situation, guest cpu thread spinning at ~100%, but display not yet initialized List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: =?UTF-8?Q?Alex_Benn=c3=a9e?= Cc: qemu-devel@nongnu.org On 11/2/2018 1:51 AM, Alex Benn=C3=A9e wrote: >=20 > Chris Friesen writes: >=20 >> Hi all, >> >> I have an odd situation which occurs very infrequently and I'm hoping >> to get some advice on how to debug. Apologies for the length of this >> message, I tried to include as much potentially useful information as >> possible. >> >> In the context of an OpenStack compute node I have a qemu guest (with >> kvm acceleration) that has started up. The virtual console shows >> "Guest has not initialized the display (yet)." I'm trying to figure >> out what's going on and how we got into this state. I assume it's >> some sort of deadlock/livelock, but I can't figure out what's causing >> it. >> At this point gdb appears to be stuck, though the task is still >> chewing 99.9% of host cpu 43. >=20 > That's because the vcpu_ioctl you just trace through is into the > VCPU_RUN, basically when you enter the guest code (assuming the in > kernel KVM code isn't spinning). That's what I figured, thanks for the confirmation. > If you want to get an idea why your guest is spinning you probably want > to enable the gdb stub and look at what your guest kernel is doing. Given the "not initialized" message on the console, I wasn't sure=20 whether the kernel had even started yet. Chris