Bug 456686 – race in aio_complete() leads to process hang

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Bug 456686 - race in aio_complete() leads to process hang

Summary:	race in aio_complete() leads to process hang

Status:	CLOSED ERRATA

Aliases:	None

Product:	Red Hat Enterprise Linux 4
Classification:	Red Hat
Component:	kernel (Show other bugs)
Sub Component:
Version:	4.7
Hardware:	All Linux

Priority	urgent Severity medium
Target Milestone:	rc
Target Release:	---
Assigned To:	Jeff Moyer
QA Contact:	Martin Jenner
Docs Contact:

URL:
Whiteboard:
Keywords:	ZStream

Depends On:
Blocks:	461304 475814 489935
	Show dependency tree / graph

Reported:	2008-07-25 11:33 EDT by Bryn M. Reeves
Modified:	2009-05-22 06:44 EDT (History)
CC List:	5 users (show)

See Also:
Fixed In Version:
Doc Type:	Bug Fix
Doc Text:
Story Points:	---
Clone Of:
Environment:
Last Closed:	2009-05-18 15:08:21 EDT
Type:	---
Regression:	---
Mount Type:	---
Documentation:	---
CRM:
Verified Versions:
Category:	---
oVirt Team:	---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---

Attachments	(Terms of Use)
Add an attachment (proposed patch, testcase, etc.)

External Trackers
Tracker	ID	Priority	Status	Summary	Last Updated
Red Hat Product Errata	RHSA-2009:1024	normal	SHIPPED_LIVE	Important: Red Hat Enterprise Linux 4.8 kernel security and bug fix update	2009-05-18 10:57:26 EDT

Groups: None (edit)

Description Bryn M. Reeves 2008-07-25 11:33:37 EDT

Description of problem:
There is a missing memory barrier in the current aio_complete in the RHEL4
kernels causing a race between read_events/aio_complete causing the thread in
read_events to sleep indefinitely, hanging the application that is waiting on
I/O completion.

This was reported upstream by Quentin Barnes of Yahoo:

http://lkml.org/lkml/2008/3/12/207

Fix has been merged in 2.6.26:

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=6cb2a21049b8990df4576c5fce4d48d0206c22d5

And was also accepted for 2.6.24.y:

http://git.kernel.org/?p=linux/kernel/git/stable/linux-2.6.24.y.git;a=commit;h=0db49fc729eee503836ea12745b55f7f802d2abb

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


How reproducible:
Unclear. Depends on the AIO application; Quentin reports seeing hangs virtually
100% of the time. Looking for a straightforward reproducer for this now and will
update with details when they are available.

Steps to Reproduce:
< to be filled >
  
Actual results:
Application hangs in read_events

Expected results:
No hang. AIO completes as normal.

Additional info:

Comment 1 RHEL Product and Program Management 2008-09-03 09:12:05 EDT

Updating PM score.

Comment 2 RHEL Product and Program Management 2008-09-22 13:53:39 EDT

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 3 Jeff Moyer 2009-01-05 14:50:24 EST

Patch posted for review:
http://post-office.corp.redhat.com/archives/rhkernel-list/2009-January/msg00042.html

Comment 4 Vivek Goyal 2009-01-15 09:04:05 EST

Committed in 78.29.EL . RPMS are available at http://people.redhat.com/vgoyal/rhel4/

Comment 12 errata-xmlrpc 2009-05-18 15:08:21 EDT

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

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