[libvirt] Incomplete stdout returned by qemu -help cause kvm disabled

[Cole Robinson]

On 04/18/2012 12:47 AM, 杨镭 wrote:
> Hi:
> 
> In our setup(libvirt 0.9.9 with Arch Linux with kernel 3.2+), when libvirt are
> accessed simultaneously, say 8 createDomain requests,  there is a large
> chance that `qemu -help` return incomplete stdout which cause kvm to be disabled.
> 
> Another user have the same situation like us[1] and he suspected this being
> the result of some race conditions. 
> 

That's now the 4th report I've seen from 3.2+ kernel users in other distros
that are seeing strange libvirt behavior. One user reported that downgrading
to 2.32 made the problems go away. So I think this is a kernel bug.

However fedora 16 doesn't have the same issue on 3.3 kernel, so maybe we have
a bug fix backported that other distros do not. See if the issue goes away
with an older kernel, and if so, file a bug with your distro and ask them to
take a look at the fedora kernel patch queue.

- Cole