Bug 652858
| Summary: | misaddresed user-space probes on prelinked shared libraries on i686 (REL) | ||
|---|---|---|---|
| Product: | Red Hat Enterprise Linux 6 | Reporter: | Roland McGrath <roland> |
| Component: | elfutils | Assignee: | Petr Machata <pmachata> |
| Status: | CLOSED ERRATA | QA Contact: | qe-baseos-tools-bugs |
| Severity: | high | Docs Contact: | |
| Priority: | low | ||
| Version: | 6.0 | CC: | drepper, ebachalo, fche, fnadge, mjw, mnewsome, pmuller, snagar |
| Target Milestone: | rc | Keywords: | Rebase, Regression |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Unspecified | ||
| Whiteboard: | |||
| Fixed In Version: | elfutils-0.152-1.el6 | Doc Type: | Rebase: Bug Fixes and Enhancements |
| Doc Text: |
Cause
After prelink has been used on the system, attempting to use systemtap user-space probes that target functions or statements in certain shared libraries or executables based on separate debuginfo will resolve to the wrong PC location in a prelinked binary.
Consequence
The intended probes will fail to fire at the correct place in the program, and the program may crash or misbehave due to a corrupted instruction sequence resulting from incorrect breakpoint insertion.
Fix
The libdwfl (libdw.so) library code was adjusted to use more reliable methods of compensating for prelink's effect on the address layout of a binary when aligning a runtime PC address with an address computed from the separate debuginfo file.
Result
The systemtap probes work the same on prelinked binaries as they do on the same binaries when they have not been adjusted by prelink.
|
Story Points: | --- |
| Clone Of: | 646871 | Environment: | |
| Last Closed: | 2011-05-19 13:13:33 UTC | Type: | --- |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
| Bug Depends On: | 652857 | ||
| Bug Blocks: | 646871 | ||
|
Description
Roland McGrath
2010-11-13 00:57:37 UTC
The bug is actually in elfutils, affecting systemtap. Bug #646871 tracks systemtap state of it, can be closed as DUP of this one if we get a proper elfutils update in the same target milestone. This is fixed in elfutils-0.150, released upstream and pending in Fedora updates. 0.151 is built in brew. We have found another related case (same bug/code, just different test case to hit this variant of it) that is a regression (vs 6.0) introduced by this fix. https://bugzilla.redhat.com/show_bug.cgi?id=674465 is the Fedora bug for the new case. We will respin this rebase to fix the regression. Yes, I have seen the issue in systemtap upstream. It's already incorporated into the test. Please be so kind and add a few key words to the technical note of this bugzilla entry using the following structure: Cause: Consequence: Fix: Result: For details, see: https://bugzilla.redhat.com/page.cgi?id=fields.html#cf_release_notes Thanks
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
New Contents:
Cause
What actions or circumstances cause this bug to present.
Consequence
What happens when the bug presents.
Fix
What was done to fix the bug.
Result
What now happens when the actions or circumstances above occur.
Note: this is not the same as the bug doesn’t present anymore.
Details written in Technical Notes field.
Technical note updated. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
Diffed Contents:
@@ -1,9 +1,8 @@
Cause
- What actions or circumstances cause this bug to present.
+ After prelink has been used on the system, attempting to use systemtap user-space probes that target functions or statements in certain shared libraries or executables based on separate debuginfo will resolve to the wrong PC location in a prelinked binary.
Consequence
- What happens when the bug presents.
+ The intended probes will fail to fire at the correct place in the program, and the program may crash or misbehave due to a corrupted instruction sequence resulting from incorrect breakpoint insertion.
Fix
- What was done to fix the bug.
+ The libdwfl (libdw.so) library code was adjusted to use more reliable methods of compensating for prelink's effect on the address layout of a binary when aligning a runtime PC address with an address computed from the separate debuginfo file.
Result
- What now happens when the actions or circumstances above occur.
+ The systemtap probes work the same on prelinked binaries as they do on the same binaries when they have not been adjusted by prelink.- Note: this is not the same as the bug doesn’t present anymore.
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-2011-0578.html |