If the diagnosis I posted above is correct, then the frequency with which this error appears will depend on both the virtualisation platform (in this case the KVM host) and the guest kernel. We virtualise CentOS 4.4 systems (2.6.9 kernel) and my colleague reports that, in two years of using VMware, he has not seen this error occur, and yet I can reliably repeat it with some frequency under KVM using Ubuntu Karmic.
If you have seen the same problem using kernels >=2.6.24, then maybe the above diagnosis is incorrect. It would be useful to verify the diagnosis by backporting the patch to the 2.6.9 kernel to find out whether it fixes the problem, but I don't really have time to do that.
It is quite easy to set up a test system: install a guest OS with "poweroff" in /etc/rc.local, and then write a script that loops calling "virsh start". Eventually the guest kernel will hang on boot, and you can connect to the console.
If the diagnosis I posted above is correct, then the frequency with which this error appears will depend on both the virtualisation platform (in this case the KVM host) and the guest kernel. We virtualise CentOS 4.4 systems (2.6.9 kernel) and my colleague reports that, in two years of using VMware, he has not seen this error occur, and yet I can reliably repeat it with some frequency under KVM using Ubuntu Karmic.
If you have seen the same problem using kernels >=2.6.24, then maybe the above diagnosis is incorrect. It would be useful to verify the diagnosis by backporting the patch to the 2.6.9 kernel to find out whether it fixes the problem, but I don't really have time to do that.
It is quite easy to set up a test system: install a guest OS with "poweroff" in /etc/rc.local, and then write a script that loops calling "virsh start". Eventually the guest kernel will hang on boot, and you can connect to the console.