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Bug 647367 - kvm: guest stale memory after migration
Summary: kvm: guest stale memory after migration
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.0
Hardware: Unspecified
OS: Unspecified
low
high
Target Milestone: rc
: 6.1
Assignee: Michael S. Tsirkin
QA Contact: Virtualization Bugs
URL:
Whiteboard:
: 642243 647964 (view as bug list)
Depends On:
Blocks: Rhel6KvmTier1 658437 683781
TreeView+ depends on / blocked
 
Reported: 2010-10-28 06:09 UTC by Michael S. Tsirkin
Modified: 2013-01-11 03:26 UTC (History)
7 users (show)

Fixed In Version: kernel-2.6.32-83.el6
Doc Type: Bug Fix
Doc Text:
Migrating a guest could have resulted in dirty values for the guest being retained in memory, which could have caused both the guest and qemu to crash. The trigger for this was memory pages being both write-protected and dirty simultaneously. With this update, memory pages in the current bitmap are either dirty or write-protected when migrating a guest, with the result that neither qemu nor guest operating systems crash following a migration.
Clone Of:
Environment:
Last Closed: 2011-05-23 20:27:46 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2011:0542 0 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 6.1 kernel security, bug fix and enhancement update 2011-05-19 11:58:07 UTC

Description Michael S. Tsirkin 2010-10-28 06:09:05 UTC 
Description of problem:
Guest memory would get olds values after migration, resulting
in guest/qemu crashes

Version-Release number of selected component (if applicable):
I reproduced this on an upstream kernel 2.6.36
But same code is in kernel-2.6.32-80.el6 so
I know it is broken there too.

How reproducible:
about 1 in 4 runs triggers this

Steps to Reproduce:
0. used intel non-ept system (should happen on all systems but this is what I have)
1. start guest 6.0 with virtio and vhost-net.
2. run netperf host to guest
3. while under stress, migrate
  
Actual results:
destination qemu exists with message 'guest moved index'

Expected results:
should keep going and complete netperf after migration

Additional info:
Try with both debug and release kernel on guest and host
Comment 3 Michael S. Tsirkin 2010-10-28 06:13:12 UTC 
Fix: commit ae8894c00b560bde4cbbc2115f532df997e15d14 upstream
Comment 6 RHEL Program Management 2010-11-04 15:59:56 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 jason wang 2010-11-05 03:26:26 UTC 
*** Bug 647964 has been marked as a duplicate of this bug. ***
Comment 8 Aristeu Rozanski 2010-11-17 19:47:26 UTC 
Patch(es) available on kernel-2.6.32-83.el6
Comment 10 Michael S. Tsirkin 2011-01-13 08:46:40 UTC 
This bug will affect vhost on and off, I think this is same as
https://bugzilla.redhat.com/show_bug.cgi?id=642243
Comment 11 Mike Cao 2011-01-13 09:50:21 UTC 
Based on https://bugzilla.redhat.com/show_bug.cgi?id=642243#c15 ,
this issue has been fix ald.
Comment 13 Michael S. Tsirkin 2011-01-31 22:23:34 UTC 
*** Bug 642243 has been marked as a duplicate of this bug. ***
Comment 14 Mike Cao 2011-02-24 06:38:52 UTC 
based on comment#11 ,change status to VERIFIED.
Comment 16 Martin Prpič 2011-04-12 12:44:44 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:
Migrating a guest could have resulted in dirty values for the guest being retained in memory, which could have caused both the guest and qemu to crash. The trigger for this was memory pages being both write-protected and dirty simultaneously. With this update, memory pages in the current bitmap are either dirty or write-protected when migrating a guest, with the result that neither qemu nor guest operating systems crash following a migration.
Comment 17 errata-xmlrpc 2011-05-23 20:27:46 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-2011-0542.html
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