Bug 671004 - user-space probes wrongly reject repnz;ret instructions
Summary: user-space probes wrongly reject repnz;ret instructions
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: systemtap
Version: 6.1
Hardware: x86_64
OS: Unspecified
low
medium
Target Milestone: rc
: ---
Assignee: Frank Ch. Eigler
QA Contact: qe-baseos-tools-bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2011-01-19 21:44 UTC by Frank Ch. Eigler
Modified: 2011-05-19 13:54 UTC (History)
2 users (show)

Fixed In Version: systemtap-1.4-2.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2011-05-19 13:54:50 UTC
Target Upstream Version:

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System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2011:0651 0 normal SHIPPED_LIVE systemtap bug fix and enhancement update 2011-05-19 09:37:25 UTC

Description Frank Ch. Eigler 2011-01-19 21:44:30 UTC 
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
risk.

commit 9ee518c4d6c36770aa5da534ae85754962bfe305
Author: Roland McGrath <roland>
Date:   Wed Jan 19 11:23:43 2011 -0800

    PR12419: fix x86 uprobes decoding of "repnz ret"
Comment 3 errata-xmlrpc 2011-05-19 13:54:50 UTC 
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.

http://rhn.redhat.com/errata/RHBA-2011-0651.html
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