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Bug 661737

Summary:	xen PV guest kernel 2.6.32 processes lock up in D state [rhel-6.0.z]
Product:	Red Hat Enterprise Linux 6	Reporter:	RHEL Program Management <pm-rhel>
Component:	kernel	Assignee:	Frantisek Hrbata <fhrbata>
Status:	CLOSED ERRATA	QA Contact:	Red Hat Kernel QE team <kernel-qe>
Severity:	high	Docs Contact:
Priority:	low
Version:	6.0	CC:	ahecox, anton, dhoward, dougsland, drjones, eric, gansalmon, itamar, jentrena, jforbes, jmalanik, kernel-maint, mishu, mshao, ngaywood, pm-eus, qcai, qwan, redhat, vevroux, xen-maint, yuzhang
Target Milestone:	rc	Keywords:	ZStream
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel-2.6.32-71.16.1.el6	Doc Type:	Bug Fix
Doc Text:	In some cases, under a small system load involve some I/O operation, processes started to lock up in the D state (that is, became unresponsive). The system load could in some cases climb steadily. This was due to the way the event channel IRQ (Interrupt Request) was set up. Xen events behave like edge-triggered IRQs, however, the kernel was setting them up as level-triggered IRQs. As a result, any action using Xen event channels could lock up a process in the D state. With this update, the handling has been changed from edge-triggered IRQs to level-triggered IRQs and process no longer lock up in the D state.	Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-02-22 17:40:30 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:	550724
Bug Blocks:

Description RHEL Program Management 2010-12-09 14:47:41 UTC

This bug has been copied from bug #550724 and has been proposed
to be backported to 6.0 z-stream (EUS).

Comment 6 errata-xmlrpc 2011-02-22 17:40:30 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-2011-0283.html

Comment 7 Martin Prpič 2011-02-23 15:07:00 UTC

    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:
In some cases, under a small system load involve some I/O operation, processes started to lock up in the D state (that is, became unresponsive). The system load could in some cases climb steadily. This was due to the way the event channel IRQ (Interrupt Request) was set up. Xen events behave like edge-triggered IRQs, however, the kernel was setting them up as level-triggered IRQs. As a result, any action using Xen event channels could lock up a process in the D state. With this update, the handling has been changed from edge-triggered IRQs to level-triggered IRQs and process no longer lock up in the D state.