Bug 495866 - show_partition() oops when race with rescan_partitions()
Summary: show_partition() oops when race with rescan_partitions()
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 5
Classification: Red Hat
Component: kernel
Version: 5.3
Hardware: All
OS: Linux
low
medium
Target Milestone: rc
: ---
Assignee: Jeff Moyer
QA Contact: Red Hat Kernel QE team
URL:
Whiteboard:
: 507758 (view as bug list)
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2009-04-15 09:09 UTC by Wengang Wang
Modified: 2009-09-02 08:58 UTC (History)
4 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2009-09-02 08:58:57 UTC
Target Upstream Version:
Embargoed:


Attachments (Terms of Use)
show_partition() oops fix patch. (1.59 KB, patch)
2009-04-15 09:11 UTC, Wengang Wang
no flags Details | Diff
Protect the per-gendisk partition array with rcu (2.11 KB, patch)
2009-07-10 14:42 UTC, Jeff Moyer
no flags Details | Diff


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2009:1243 0 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 5.4 kernel security and bug fix update 2009-09-01 08:53:34 UTC

Description Wengang Wang 2009-04-15 09:09:04 UTC
problem is same as bug https://bugzilla.redhat.com/show_bug.cgi?id=495858, but this is for EL5.

Comment 1 Wengang Wang 2009-04-15 09:11:11 UTC
Created attachment 339654 [details]
show_partition() oops fix patch.

the patch fixes the oops.
it's based on kernel 2.6.18-128
please have it included in next release.

Comment 2 Lachlan McIlroy 2009-06-24 05:45:29 UTC
*** Bug 507758 has been marked as a duplicate of this bug. ***

Comment 3 Jeff Moyer 2009-07-10 14:42:10 UTC
Created attachment 351271 [details]
Protect the per-gendisk partition array with rcu

This is basically the same patch, but protecting /proc/diskstats accesses with rcu as well.

Comment 4 Jeff Moyer 2009-07-10 14:44:28 UTC
I ran the above patch through the following test for 16 hours or so without failure:

# while true; do cat /proc/diskstats > /dev/null; done &
# while true; do cat /proc/partitions > /dev/null; done &
# while true; do hdparm -z /dev/sdd; done

Prior to the patch, I could get a failure within seconds.

Comment 5 RHEL Program Management 2009-07-10 15:03:34 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 7 Don Zickus 2009-07-14 20:57:01 UTC
in kernel-2.6.18-158.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.

Comment 10 errata-xmlrpc 2009-09-02 08:58:57 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-2009-1243.html


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