From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:34363) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SmR0w-0002BM-Q8 for qemu-devel@nongnu.org; Wed, 04 Jul 2012 10:57:16 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SmR0t-0000CY-U1 for qemu-devel@nongnu.org; Wed, 04 Jul 2012 10:57:10 -0400 Received: from ssl.dlhnet.de ([91.198.192.8]:46508 helo=ssl.dlh.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SmR0t-0000C8-NR for qemu-devel@nongnu.org; Wed, 04 Jul 2012 10:57:07 -0400 Message-ID: <4FF459C0.2060608@dlhnet.de> Date: Wed, 04 Jul 2012 16:57:04 +0200 From: Peter Lieven MIME-Version: 1.0 References: <4FEB2945.1030607@dlhnet.de> <4FEB3AC6.6010206@web.de> <4FEC1FC9.7050103@dlhnet.de> <4FEC2210.1030005@siemens.com> <4FEC2475.4030202@dlhnet.de> <4FEC2626.90402@dlhnet.de> <4FF1B8A6.2020101@redhat.com> <4FF2ED2A.7080300@dlhnet.de> <4FF2EFE0.2090400@redhat.com> <4FF2F058.1010601@dlhnet.de> <4FF2F2D7.2050207@redhat.com> In-Reply-To: <4FF2F2D7.2050207@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] race between kvm-kmod-3.0 and kvm-kmod-3.3 // was: race condition in qemu-kvm-1.0.1 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Avi Kivity Cc: Jan Kiszka , Gleb Natapov , qemu-devel@nongnu.org, kvm@vger.kernel.org On 07/03/12 15:25, Avi Kivity wrote: > On 07/03/2012 04:15 PM, Peter Lieven wrote: >> On 03.07.2012 15:13, Avi Kivity wrote: >>> On 07/03/2012 04:01 PM, Peter Lieven wrote: >>>> Further output from my testing. >>>> >>>> Working: >>>> Linux 2.6.38 with included kvm module >>>> Linux 3.0.0 with included kvm module >>>> >>>> Not-Working: >>>> Linux 3.2.0 with included kvm module >>>> Linux 2.6.28 with kvm-kmod 3.4 >>>> Linux 3.0.0 with kvm-kmod 3.4 >>>> Linux 3.2.0 with kvm-kmod 3.4 >>>> >>>> I can trigger the race with any of qemu-kvm 0.12.5, 1.0 or 1.0.1. >>>> It might be that the code was introduced somewhere between 3.0.0 >>>> and 3.2.0 in the kvm kernel module and that the flaw is not >>>> in qemu-kvm. >>>> >>>> Any hints? >>>> >>> A bisect could tell us where the problem is. >>> >>> To avoid bisecting all of linux, try >>> >>> git bisect v3.2 v3.0 virt/kvm arch/x86/kvm >>> >>> >> would it also be ok to bisect kvm-kmod? > Yes, but note that kvm-kmod is spread across two repositories which are > not often tested out of sync, so you may get build failures. > ok, i just started with this with a 3.0 (good) and 3.2 (bad) vanilla kernel. i can confirm the bug and i am no starting to bisect. it will take while with my equipment if anyone has a powerful testbed to run this i would greatly appreciate help. if anyone wants to reproduce: a) v3.2 from git.kernel.org b) qemu-kvm 1.0.1 from sourceforge c) ubuntu 64-bit 12.04 server cd d) empty (e.g. all zero) hard disk image cmdline: ./qemu-system-x86_64 -m 512 -cdrom /home/lieven/Downloads/ubuntu-12.04-server-amd64.iso -hda /dev/hd1/vmtest -vnc :1 -monitor stdio -boot dc then choose boot from first harddisk and try to quit the qemu monitor with 'quit'. -> hypervisor hangs. peter