Jim, patches relative to RHEL4 are in comments 3 and 4 of bug 154451.
I originally labelled this issue as CAN-2005-0756 however that was in error due
to two similar ptrace check issues. The following is as reported to vendor-sec:
Fixing rip -> CAN-2005-1762
Fixing fs_base and gs_base -> CAN-2005-0756
[PATCH] x86_64: check if ptrace RIP is canonical
This works around an AMD Erratum.
This is a DoS on 2.4 and 2.6
A fix for this problem has just been committed to the RHEL3 U6
patch pool this evening (in kernel version 2.4.21-32.8.EL).
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.