Installed hudson, configured hudson, installed some plugins, all fine. Installed the libvirt plugin and got the first lockup when starting, that one was fixed, now when disabling or entirely removing the plugin, the locks are back again (I am able to start hudson after enabling the plugin again). Also cannot create a dumb slave (may or may not be related) with the plugin enabled.

jstack after disabling libvirt and restarting: http://fpaste.org/6a6T/raw/
jstack after removing libvirt and restarting: http://fpaste.org/hU4j/raw/
error when creating a dumb node with libvirt enabled: http://fpaste.org/r6vX/raw/