Re: [fedora-virt] libvirtd crashes host when autostarting

[Paul Lambert]

Rich, Mark,

I experienced this problem as well when using a FE-11 host and FE-11 Guest.
I now have FE-12-alpha installed but have been afraid to try it until I know
if this issue was addressed in the new version.

Configuring a guest to start on host bootup totally hoses the host.  The
only way to recover is to boot off of a CD and then find the startup
directory and delete the link to the guest.  The host will reboot OK after
this.

By the way Mark, still no mounting for USB disks with FE-12-Alpha.  Up to
date on patches as of 10/8/2009.

Paul

On Fri, Oct 9, 2009 at 9:53 AM, Mark McLoughlin <markmc(a)redhat.com&gt; wrote:

>  On Fri, 2009-10-09 at 09:45 -0400, Rich Mahn wrote:
>  > Summary:
>  >    My host crashes when I use the autostart function in
>  > libvirtd.
>  >
>  > This command sequence works fine:
>  >
>  > service libvirtd stop
>  > virsh autostart mydomain --disable
>  > service lib virtd start
>  > virsh start mydomain
>  >
>  > This command sequence will crash the host:
>  >
>  > service libvirtd stop
>  > virsh autostart mydomain
>  > service libvirtd start
>  >
>  >
>  > I can't find any error messages related to this.  The host system
>  > freezes, the keyboard starts blinking the caps-lock and scroll-lock,
>  > and as best I can tell, the kernel has stopped running.
>
>  Ouch, that's really bad. This is a 2.6.30 kernel, right? Is it still
>  reproducible with an older 2.6.29 kernel or a 2.6.31 kernel from
>  rawhide?
>
>  This is ultimately a kernel bug, userspace shouldn't be able to screw up
>  the kernel like this.
>
>  It'd be good to get this into bugzilla:
>
>   https://fedoraproject.org/wiki/Reporting virtualization bugs
>
>  > If I starting up the host system with the VM autostarted, I sometimes
>  > get messages that look like kernel errors on the screen, but I don't
>  > find them in any log files so far.  They seem to be related to
>  networking.
>  >
>  > Here's some configuration information--I don't know really what all is
>  > needed, but this, I guess is a start:
>  >
>  > Host and VM both Fedora 11 with the lastest updates.
>  > Host machine in Intel based with the virtual support turned on.
>  >
>  > In the /var/log/libvirtd/qemu directory, the command line to start
>  > the virtual machine is different when started from autostart.  The
>  > difference is in this portion:
>  >
>  >           -net tap,fd=11,vlan=0       for failure (autostart) and
>  >           -net tap,fd=18,vlan=0       for success
>
>  Interesting, but I can't immediately think where the difference may come
>  from or how it could be related to the kernel lockup.
>
>  Cheers,
>  Mark.
>
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