Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.
RHEL Engineering is moving the tracking of its product development work on RHEL 6 through RHEL 9 to Red Hat Jira (issues.redhat.com). If you're a Red Hat customer, please continue to file support cases via the Red Hat customer portal. If you're not, please head to the "RHEL project" in Red Hat Jira and file new tickets here. Individual Bugzilla bugs in the statuses "NEW", "ASSIGNED", and "POST" are being migrated throughout September 2023. Bugs of Red Hat partners with an assigned Engineering Partner Manager (EPM) are migrated in late September as per pre-agreed dates. Bugs against components "kernel", "kernel-rt", and "kpatch" are only migrated if still in "NEW" or "ASSIGNED". If you cannot log in to RH Jira, please consult article #7032570. That failing, please send an e-mail to the RH Jira admins at rh-issues@redhat.com to troubleshoot your issue as a user management inquiry. The email creates a ServiceNow ticket with Red Hat. Individual Bugzilla bugs that are migrated will be moved to status "CLOSED", resolution "MIGRATED", and set with "MigratedToJIRA" in "Keywords". The link to the successor Jira issue will be found under "Links", have a little "two-footprint" icon next to it, and direct you to the "RHEL project" in Red Hat Jira (issue links are of type "https://issues.redhat.com/browse/RHEL-XXXX", where "X" is a digit). This same link will be available in a blue banner at the top of the page informing you that that bug has been migrated.

Bug 1446498

Summary: Guest freeze after live snapshot with data-plane
Product: Red Hat Enterprise Linux 7 Reporter: Qianqian Zhu <qizhu>
Component: qemu-kvm-rhevAssignee: Stefan Hajnoczi <stefanha>
Status: CLOSED ERRATA QA Contact: Qianqian Zhu <qizhu>
Severity: high Docs Contact:
Priority: high    
Version: 7.4CC: chayang, famz, juzhang, knoel, michen, pbonzini, qizhu, virt-maint, xfu
Target Milestone: rcKeywords: Regression
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: qemu-kvm-rhev-2.9.0-5.el7 Doc Type: If docs needed, set a value
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2017-08-02 04:35:59 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Qianqian Zhu 2017-04-28 08:47:45 UTC
Description of problem:
Guest hang after live snapshot with data-plane

Version-Release number of selected component (if applicable):
qemu-kvm-rhev-2.9.0-1.el7.x86_64
kernel-3.10.0-643.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Launch guest with data-plane:
/usr/libexec/qemu-kvm \
    -name 'avocado-vt-vm1'  \
    -vga cirrus  \
    -object iothread,id=iothread0 \
    -device virtio-scsi-pci,iothread=iothread0,id=virtio_scsi_pci0,bus=pci.0,addr=03 \
    -drive id=drive_image1,if=none,snapshot=off,aio=native,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/rhel74-64-virtio-scsi.qcow2 \
    -device scsi-hd,id=image1,drive=drive_image1 \
    -device virtio-net-pci,mac=9a:ac:ad:ae:af:b0,id=idqKTtyC,vectors=4,netdev=idBAxKKY,bus=pci.0,addr=04  \
    -netdev tap,id=idBAxKKY,vhost=on \
    -m 4096  \
    -smp 4,cores=2,threads=1,sockets=2  \
    -cpu 'SandyBridge',+kvm_pv_unhalt \
    -vnc :0  \
    -rtc base=utc,clock=host,driftfix=slew  \
    -boot order=cdn,once=c,menu=off,strict=off \
    -monitor stdio \
    -qmp tcp::5555,server,nowait

2. Live snapshot:
{'execute': 'blockdev-snapshot-sync', 'arguments': {'device': 'drive_image1', 'snapshot-file': '/home/kvm_autotest_root/images/sn1', 'mode': 'absolute-paths', 'format': 'qcow2'}, 'id': 'Wh5neQ4H'}

3. Check guest

Actual results:
Guest freeze, no response to mouse and keyboard. Tt's able to ping, but can't ssh login.

Expected results:
Guest works well.

Additional info:
qemu-kvm-rhev-2.6.0-27.el7.x86_64 works well, so this is a regression.

Comment 3 Fam Zheng 2017-05-04 08:49:08 UTC
Can you collect the backtrace of all threads when it hangs?

Comment 4 Fam Zheng 2017-05-04 10:09:19 UTC
Stefan managed to reproduce this and we've located the root cause. Backtrace doesn't really help here, the issue is the iothread didn't get awakened correctly by aio_enable_external(). Clearing the needinfo therefore.

A fix will need to be worked on upstream.

Comment 5 Stefan Hajnoczi 2017-05-04 10:24:41 UTC
I've posted a patch upstream ("[PATCH] aio: add missing aio_notify() to aio_enable_external()") and will backport it.

Comment 6 Stefan Hajnoczi 2017-05-15 14:26:45 UTC
Patch posted downstream.

Comment 7 Miroslav Rezanina 2017-05-16 13:03:53 UTC
Fix included in qemu-kvm-rhev-2.9.0-5.el7

Comment 9 Qianqian Zhu 2017-05-17 02:35:26 UTC
Verified on:
qemu-kvm-rhev-2.9.0-5.el7.x86_64
kernel-3.10.0-640.el7.x86_64

Steps same as comment 0, add block stream test afterwards.
Result:
As expected, guest works well after live snapshot and block stream.

Moving to VERIFIED.

Comment 11 errata-xmlrpc 2017-08-02 04:35:59 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:2392