Red Hat Bugzilla – Bug 671004
user-space probes wrongly reject repnz;ret instructions
Last modified: 2011-05-19 09:54:50 EDT
GCC sometimes emits the code sequence "repnz;ret" to end a function.
systemtap's uprobes module rejects that as an unknown instruction
sequence, but this is unnecessary. We have a patch in hand to let
such instructions be treated just like "rep;ret" = "ret". This
should let stap run even with such optimized gcc code, without
Author: Roland McGrath <email@example.com>
Date: Wed Jan 19 11:23:43 2011 -0800
PR12419: fix x86 uprobes decoding of "repnz ret"
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 therefore 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.