Bug 442579

Summary: Backport fix for possible data corruption in mark_buffer_dirty on SMP
Product: Red Hat Enterprise Linux 4 Reporter: Mikuláš Patočka <mpatocka>
Component: kernelAssignee: Mikuláš Patočka <mpatocka>
Status: CLOSED ERRATA QA Contact: Martin Jenner <mjenner>
Severity: medium Docs Contact:
Priority: medium    
Version: 4.8CC: agk, christophe.varoqui, dwysocha, edamato, egoggin, heinzm, jbrassow, junichi.nomura, kueda, lmb, mbroz, prockai, tranlan
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
URL: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=1be62dc190ebaca331038962c873e7967de6cc4b;hp=4ed919014eb2b591eb8fdd4dd00226a65faddef4
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-05-18 19:32:32 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: 442577    
Bug Blocks: 461304    

Description Mikuláš Patočka 2008-04-15 16:50:20 UTC
+++ This bug was initially created as a clone of Bug #442577 +++

Description of problem:

Function mark_buffer_dirty() contains SMP-unsafe optimization. If CPU reorders
instructions in certain way, it may cause that modified data are not written and
filesystem corruption happens.

For discussion, see the thread at
http://www.uwsg.indiana.edu/hypermail/linux/kernel/0804.0/0854.html

There are several possible fixes with different performance and complexity (see
the thread), the one that went into upstream kernel is this:
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=1be62dc190ebaca331038962c873e7967de6cc4b;hp=4ed919014eb2b591eb8fdd4dd00226a65faddef4

Version-Release number of selected component (if applicable):
All

How reproducible:
Can't be reproduced, was found during source code review.
If data corruption because of this bug ever happened, it would be very hard to
link the corruption to this problem --- so maybe it would be better to fix the
bug preemtively.

Comment 1 RHEL Program Management 2008-04-15 18:09:56 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.

Comment 2 RHEL Program Management 2008-09-03 13:10:23 UTC
Updating PM score.

Comment 3 Vivek Goyal 2008-09-12 19:58:05 UTC
Committed in 78.9.EL . RPMS are available at http://people.redhat.com/vgoyal/rhel4/

Comment 6 errata-xmlrpc 2009-05-18 19:32:32 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/RHSA-2009-1024.html