Bug 524920

Summary:	cannot bring cpus back online
Product:	Red Hat Enterprise Linux 5	Reporter:	Glauber Costa <gcosta>
Component:	kvm	Assignee:	Eduardo Habkost <ehabkost>
Status:	CLOSED CURRENTRELEASE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	medium	Docs Contact:
Priority:	low
Version:	5.4	CC:	ehabkost, lihuang, virt-maint, ykaul
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:	kernel-2.6.18-170.el5	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-01-27 13:04:45 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:	510814
Bug Blocks:

Description Glauber Costa 2009-09-22 17:33:11 UTC

Description of problem:


If we offline a cpu, we can no longer put it back with our latest kernel
This only happens with the kvm-kmod module enabled. Without it, it goes fine.

Version-Release number of selected component (if applicable):
2.6.18-164.el5 

How reproducible:
always

Steps to Reproduce:
1. echo 0 > /sys/devices/system/cpu/cpuX/online
2. echo 1 > /sys/devices/system/cpu/cpuX/online
3.
  
Actual results:
cpu goes down, but do not come back


Expected results:
it goes down, but then comes back again

Comment 1 Eduardo Habkost 2009-09-22 17:36:52 UTC

Host CPU hotplug isn't supported with the KVM modules loaded: https://bugzilla.redhat.com/show_bug.cgi?id=516122

We need this to make it work:
https://bugzilla.redhat.com/show_bug.cgi?id=510814

Comment 2 Eduardo Habkost 2009-09-22 17:38:00 UTC

Oops, I pasted the wrong URL. The cpu-hotplug-not-supported bug is:
https://bugzilla.redhat.com/show_bug.cgi?id=515557

Comment 5 Eduardo Habkost 2009-10-15 19:15:39 UTC

Should be fixed by the fix for bug #510814. Moving to POST to reflect the fix status.

Comment 6 Eduardo Habkost 2009-10-21 19:30:59 UTC

The fix for bug #510814 (that should solve this bug) is in kernel-2.6.18-170.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Testing is welcome.

Comment 8 Eduardo Habkost 2009-10-27 19:40:53 UTC

Moving bug to KVM, as the kernel side of the change (and probably the only change needed) is bug #510814.

Comment 9 lihuang 2009-10-28 02:22:12 UTC

test in kernel-2.6.18-170.el5/ kmod-kvm-83-105.el5_4.9
PASS 
(refer to Bug 515557#c23)

Comment 10 lihuang 2010-01-31 12:10:07 UTC

retest in kernel -185.el5. PASS

Comment 11 lihuang 2010-01-31 12:11:11 UTC

setting to VERIFIED.