Description of problem:
After rebooting the dom0, two guests have come back up without a ticking clock.
 dom0 is running xendomains so the guests were automatically save/restored over
the reboot.

[root@dhcp-0-208 ~]# date
Thu Jan 24 11:18:08 GMT 2008
[root@dhcp-0-208 ~]# date
Thu Jan 24 11:18:08 GMT 2008
[root@dhcp-0-208 ~]# date
Thu Jan 24 11:18:08 GMT 2008

This corresponds roughly to the time at which the guest state would have been saved:

reboot   system boot  2.6.18-53.1.6.el Thu Jan 24 11:20          (00:02)    
root     pts/4        vpn-6-11.fab.red Thu Jan 24 11:15 - down   (00:01)    
root     pts/0        vpn-6-11.fab.red Thu Jan 24 11:10 - down   (00:07)    

The guests seem otherwise fine; userspace is working albeit system calls act as
if time stands still (e.g. poll doesn't time out, nanosleep sleeps forever).

Version-Release number of selected component (if applicable):
dom0: 2.6.18-53.1.6.el5xen
guest: 2.6.18-53.el5xen

How reproducible:
This has affected 2/6 guests on the system; 4 of which were running RHEL 5.1