Bug 543270

Summary: Fix deadlock in multipath when removing a device
Product: Red Hat Enterprise Linux 5 Reporter: Mikuláš Patočka <mpatocka>
Component: kernelAssignee: Mikuláš Patočka <mpatocka>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.5CC: bdonahue, coughlan, eyal.gordon, jtluka
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
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Clone Of: Environment:
Last Closed: 2010-03-30 07:36:42 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:    
Bug Blocks: 527501    
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Description Flags
The backported patch none

Comment 1 RHEL Program Management 2009-12-02 02:31:40 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 Don Zickus 2009-12-11 19:31:42 UTC
in kernel-2.6.18-179.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please update the appropriate value in the Verified field
(cf_verified) to indicate this fix has been successfully
verified. Include a comment with verification details.

Comment 5 Barry Donahue 2010-02-19 17:54:57 UTC
    What are the steps to reproduce this problem?

Comment 6 Tom Coughlan 2010-02-25 21:44:29 UTC
<mikulas> coughlan: this is a race condition, when failing a path and removing the mpath device simultaneously causes the deadlock.
<mikulas> coughlan: if you want to reliably reproduce the race, you must artifically delay the thread that submits the events.
<mikulas> coughlan: I would recommend adding a msleep(10000) (ten seconds) at the beginning of trigger_event function.
<mikulas> then, fail the path and within 10 seconds, remove the device. I think that should trigger the bug.
<mikulas> (note, by removing the device, I mean "dmsetup remove <device>")
<mikulas> if it doesn't work (something during device removal uses the same event thread), another option how to reproduce it would be to remove schedule_work(&m->trigger_event); from dm-mpath.c

Comment 8 errata-xmlrpc 2010-03-30 07:36:42 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-2010-0178.html

Comment 9 Mikuláš Patočka 2010-11-28 05:33:12 UTC
*** Bug 555266 has been marked as a duplicate of this bug. ***