Bug 604188

Summary: Guest suffers kernel panic when save snapshot then restart guest
Product: Red Hat Enterprise Linux 5 Reporter: RHEL Product and Program Management <pm-rhel>
Component: kvmAssignee: Virtualization Maintenance <virt-maint>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: high Docs Contact:
Priority: high    
Version: 5.5CC: apevec, cpelland, kwolf, llim, mgoldboi, mkenneth, ovirt-maint, pm-eus, qzhang, tburke, virt-maint, ykaul
Target Milestone: rcKeywords: Reopened, ZStream
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: kvm-83-164.el5_5.12 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2010-06-22 14:40:16 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---
Bug Depends On: 542954    
Bug Blocks: 556823    

Description RHEL Product and Program Management 2010-06-15 15:03:24 UTC
This bug has been copied from bug #542954 and has been proposed
to be backported to 5.5 z-stream (EUS).

Comment 6 Lawrence Lim 2010-06-17 02:48:06 UTC
Comment from Kevin, QE please take note and make sure the suggestions made by
Kevin are well covered.

=======================

Anything that uses lots of synchronous reads/writes (i.e. metadata
operations). Long snapshots chains where a lot of COW happens seems to
be a good candidate.

It's probably enough to test intensively with one backing file format,
preferably qcow2 which may issue synchronous metadata I/O again and
therefore makes the scenario more complex.

For verification of the fix, you need to use virtio-blk (multiple
requests running at once are required to even trigger this bug). On the
other hand, only IDE can directly call synchronous bdrv_read/write which
is touched by this patch, so in order to avoid regressions some tests on
IDE should be run, too.

Kevin

Comment 7 Qunfang Zhang 2010-06-17 07:19:42 UTC
Tested with the steps in bug #542954, and that issue does not happen on kvm-83-164.el5_5.12. Besides, we will do more test for this bug, and will upload the test result after finished.

Comment 8 Qunfang Zhang 2010-06-18 11:01:05 UTC
Test runners for verifying this bug:
https://tcms.engineering.redhat.com/run/10370/ (NFS)
https://tcms.engineering.redhat.com/run/10369/ (block device)

Result: Passed.
kvm version: kvm-83-164.el5_5.12

Comment 11 errata-xmlrpc 2010-06-22 14:40:16 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/RHBA-2010-0479.html