Doesn't look like it affects CentOS that much:
$ ./diagnose-2010-3081
Diagnostic tool for public CVE-2010-3081 exploit -- Ksplice, Inc.
(see
http://www.ksplice.com/uptrack/cve-2010-3081)
$$$ Kernel release: 2.6.18-194.11.1.el5xen
$$$ Backdoor in LSM (1/3): not available.
$$$ Backdoor in timer_list_fops (2/3): not available.
$$$ Backdoor in IDT (3/3): checking...not present.
Your system is free from the backdoors that would be left in memory
by the published exploit for CVE-2010-3081.
$ cat /etc/redhat-release
CentOS release 5.5 (Final)