[CentOS] Kernel BUG

The message seems  problem is on disk io.
This "child_rip" handler erases everything in shutting down sequences,
 but kernel object already erased.
Its cause from ..
1. some driver double freed a same object. (driver problem)
2. heavy new/delete events double frees a same object(environment problem)

To resolve your problem, keep your disk access stably.
I saw you use xen kernel to ask xen-expert.
HOST and GEST can't handle like memory problem on VM environment,
 Reduce I/O,
 Change your hypervisor.

you can try many version of kernel-xen on centos.(or Xenserver)
you can reduce your traffic on your environment.(or upgrade your system ;)

-Tsuyoshi