From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: fedora 10 x86_64 breakage under KVM, due to KVM_CLOCK Date: Mon, 20 Apr 2009 14:56:12 +0300 Message-ID: <49EC62DC.5080900@redhat.com> References: <20090420112613.GA1860@mail.wantstofly.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, lfarkas@lfarkas.org, davej@codemonkey.org.uk To: Lennert Buytenhek Return-path: Received: from mx2.redhat.com ([66.187.237.31]:48514 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754778AbZDTL4W (ORCPT ); Mon, 20 Apr 2009 07:56:22 -0400 In-Reply-To: <20090420112613.GA1860@mail.wantstofly.org> Sender: kvm-owner@vger.kernel.org List-ID: Lennert Buytenhek wrote: > (please CC, not on the list) > > Hi all, > > Fedora 10 randomly hangs for me when run under KVM, whereas (unpatched) > F9 works fine. When this happens, kvm_stat shows that the VM is seeing > 1000 IRQ exits per second, but nothing else seems to happen. The latest > F9 update kernel seems to be bust as well. (I noticed that the KVM guest > support status page says that "Alexey E." is seeing the same thing.) > > I tried about two dozen different kernel packages from koji, and it turns > out that kernel-2.6.26-0.122.rc9.git4.fc10 is the last known good kernel, > and kernel-2.6.26-0.124.rc9.git5.fc10 is the first kernel that's broken. > > The F10 instability appears since this commit (attached below as well): > > http://fedora.gitbits.net/?p=kernel;a=commit;h=a5991f36968f44d4d3c64fc5aaa285a21de1ba54 > > I built three new kernels from the latest 2.6.27-170.2.56.fc10 update > in Fedora 10: > 1. One with PARAVIRT and all associated options disabled entirely. > 2. One with only KVM_GUEST disabled. > 3. One with only KVM_CLOCK disabled (and paravirt and KVM_GUEST enabled). > > Kernel (1) is stable. Kernel (2) is unstable like the unpatched F10 > kernels are, in that it randomly locks up. Kernel (3) is stable as > well, which suggests that KVM_CLOCK is what's causing the lockups. > > I tried booting the original F10 update kernel with no-kvmclock on > the command line as well, and that makes things stable as well. > > I tried with the latest F10 updates-testing kernel (2.6.29.1-30.fc10), > and that shows the same thing: with no-kvmclock it works fine, otherwise > it hangs randomly. > > Running KVM 84 on x86_64 CentOS 5.3, with the kvm rpms from lfarkas.org. > The host CPU is a Q6600 Core 2 Quad. > > Any ideas? > This is a known issue. While kvm-84 fixed kvmclock, an issue remained with cpu frequency scaling on older host kernels (including RHEL 5 / CentOS 5). kvm-85 (to be released shortly) contains a fix (b395d156477a in kvm-userspace.git). -- error compiling committee.c: too many arguments to function