[CentOS] strace issue in 5.5?

Hello,

I am trying to get some more information about the following issue:

# strace -p 2256
attach: ptrace(PTRACE_ATTACH, ...): Operation not permitted

I am trying to trace an mdadm re-sync pid and I keep getting the above
error.

I have done some digging on google and forums, but have not had much luck.

Redhat-release says

CentOS release 5.5 (Final)

uname:
2.6.18-194.32.1.el5

Any help would be great.

-Eric
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