Comment 29 for bug 1254890

See also bug #1277494 - in this case, a thread appears to get stuck in libvirt driver's to_xml() function

To see if this is the issue with a given failure do:

   grep '\(Start\|End\) to_xml' screen-n-cpu.txt.gz

if the last result from this grep is 'Start to_xml()', it could be the same problem

Would be good to figure out whether this is just a once off underlying cause of a timeout, or more common