From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53356) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eWgzp-0005sO-Ro for qemu-devel@nongnu.org; Wed, 03 Jan 2018 06:14:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eWgzn-0005fl-5B for qemu-devel@nongnu.org; Wed, 03 Jan 2018 06:14:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:36704) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eWgzm-0005f8-VI for qemu-devel@nongnu.org; Wed, 03 Jan 2018 06:14:07 -0500 References: <5a4c49c8.50b91c0a.2b051.322e@mx.google.com> From: Paolo Bonzini Message-ID: Date: Wed, 3 Jan 2018 12:14:00 +0100 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] stable/linux-4.14.y boot: 108 boots: 0 failed, 107 passed with 1 conflict (v4.14.11) List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Thomas Gleixner , Guillaume Tucker Cc: Dave Hansen , Ingo Molnar , Greg Kroah-Hartman , kernel-build-reports@lists.linaro.org, Matt Hart , stable@vger.kernel.org, LKML , x86@kernel.org, Andy Lutomirski , Peter Zijlstra , qemu-devel@nongnu.org On 03/01/2018 11:36, Thomas Gleixner wrote: > On Wed, 3 Jan 2018, Guillaume Tucker wrote: >> On 03/01/18 09:48, Thomas Gleixner wrote: >>>> Well, it turns out this is not exactly a conflict as there's a >>>> subtle difference between the qemu devices in lab-mhart and in >>>> lab-collabora. The ones in lab-collabora are configured to use >>>> KVM, and it looks like the ones in lab-mhart aren't. >>>> >>>> So this job with KVM enabled passes in lab-collabora: >>>> >>>> https://lava.collabora.co.uk/scheduler/job/1032358 >>>> >>>> but it fails if I tell LAVA (qemu) to disable KVM: >>>> >>>> https://lava.collabora.co.uk/scheduler/job/1032359 >>>> >>>> with the same panic as in lab-mhart. It seems like it's failing >>>> to return from an interrupt: >>>> >>>> http://lava.streamtester.net/scheduler/job/87308 >>>> >>>> [ 2.678828] ? native_iret+0x7/0x7 >>>> [ 2.679208] WARNING: can't dereference iret registers at >>>> 00000000ffc66068 >>>> for ip page_fault+0x11/0x60 >>>> >>>> This triggered an automated bisection on kernelci.org, please see >>>> the results below. >>>> >>>> I may run another bisection with this config enabled earlier in >>>> the history to track down the actual change in the code that >>>> introduced the issue, let me know if it's worth doing. >>> >>> No, because before that commit not all pieces are in place. >>> >>> Can you please try the failing kernel with pti=off on the command line? >> >> It does boot with pti=off (and KVM disabled): >> >> https://lava.collabora.co.uk/scheduler/job/1032387 > > So it's a qemu issue. Added qemu folks on Cc. Reproduced, thanks. I will look into it. Paolo