Fedora xen - Nov 2009 - problems with F11 domU on a centos 5 host

hi

i m trying to use a F11 xen guest on a centos 5 machine. the guest is 
fully virtualized
and from time to time i found my guest completely unresponsive.
it eating all his cpu and the only way i found to get it back is to 
shutdown it.
Has anybody already seen that kind of problem?


on the host i have xen-3.0.3-80.
Thanks in advance for any help