Note: This bug is displayed in read-only format because the product is no longer active in Red Hat Bugzilla.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 1218577

Summary: iothreaddel can make a vm have broken settings which will make vm lose track after restart libvirtd
Product: Red Hat Enterprise Linux 7 Reporter: Luyao Huang <lhuang>
Component: libvirtAssignee: John Ferlan <jferlan>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.2CC: dyuan, honzhang, mzhan, rbalakri, shyu
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: libvirt-1.2.16-1.el7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-11-19 06:30:06 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 Luyao Huang 2015-05-05 09:48:56 UTC
description of problem:
iothreaddel can make a vm have broken settings which will make vm
lose track after restart libvirtd

Version-Release number of selected component (if applicable):
libvirt-1.2.15-1.el7.x86_64
qemu-kvm-rhev-2.3.0-1.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.
prepare a offline vm:

# virsh dumpxml test3

  <iothreads>2</iothreads>
  <iothreadids>
    <iothread id='1'/>
  </iothreadids>

2. start it
# virsh start  test3
Domain test3 started

3.
# virsh iothreadinfo test3
 IOThread ID     CPU Affinity  
---------------------------------------------------
 1               0-3
 2               0-3

4.
use iothreaddel remove thread 1

# virsh iothreaddel test3 1

5.
bind thread 2 to cpu 1

# virsh iothreadpin test3 2 1

# virsh dumpxml test3
  <iothreads>1</iothreads>
  <cputune>
    <iothreadpin iothread='2' cpuset='1'/>
  </cputune>


6. check the cgroup

# cgget -g cpuset /machine.slice/machine-qemu\\x2dtest3.scope/iothread2
/machine.slice/machine-qemu\x2dtest3.scope/iothread2:
cpuset.memory_spread_slab: 0
cpuset.memory_spread_page: 0
cpuset.memory_pressure: 0
cpuset.memory_migrate: 1
cpuset.sched_relax_domain_level: -1
cpuset.sched_load_balance: 1
cpuset.mem_hardwall: 0
cpuset.mem_exclusive: 0
cpuset.cpu_exclusive: 0
cpuset.mems: 0
cpuset.cpus: 1

7. restart libvirtd vm will lose track:

# virsh list
 Id    Name                           State
----------------------------------------------------

8. check the log

2015-05-05 06:29:48.382+0000: 17710: error : virDomainIOThreadPinDefParseXML:13374 : unsupported configuration: Cannot find 'iothread' : 2

Actual results:
iothreaddel can make a vm have broken settings which will make vm
lose track after restart libvirtd

Expected results:
guest still exist after restart libvirtd

infomation:

Comment 1 John Ferlan 2015-05-06 14:51:49 UTC
Posted patches upstream:

http://www.redhat.com/archives/libvir-list/2015-May/msg00156.html

Comment 2 John Ferlan 2015-05-14 12:56:59 UTC
Pushed a fix upstream to resolve this:

commit 361801362fb047ceb63e303efec224aea73a179a
Author: John Ferlan <jferlan>
Date:   Wed May 6 10:19:30 2015 -0400

    qemu: Clear autofil fill flag when pinning iothread
    


git describe 361801362fb047ceb63e303efec224aea73a179a
v1.2.15-79-g3618013

Comment 4 Luyao Huang 2015-07-30 07:19:34 UTC
Verify this bug with libvirt-1.2.17-2.el7.x86_64:

1. 

# virsh dumpxml rhel7.0-rhel |grep iothread
  <iothreads>2</iothreads>
  <iothreadids>
    <iothread id='1'/>
  </iothreadids>

2. 
# virsh start rhel7.0-rhel
Domain rhel7.0-rhel started

3.
# virsh iothreadinfo rhel7.0-rhel
 IOThread ID     CPU Affinity   
---------------------------------------------------
 1               0-3
 2               0-3

4.
# virsh iothreaddel rhel7.0-rhel 1

5.
# virsh iothreadinfo rhel7.0-rhel
 IOThread ID     CPU Affinity   
---------------------------------------------------
 2               0-3

6.
# virsh dumpxml rhel7.0-rhel |grep iothread
  <iothreads>1</iothreads>
  <iothreadids>
    <iothread id='2'/>
  </iothreadids>

7.
# virsh iothreadpin rhel7.0-rhel 2 1

8.
# virsh dumpxml rhel7.0-rhel |grep iothread
  <iothreads>1</iothreads>
  <iothreadids>
    <iothread id='2'/>
  </iothreadids>
    <iothreadpin iothread='2' cpuset='1'/>

9.

# virsh list
 Id    Name                           State
----------------------------------------------------
 16    rhel7.0-rhel                   running

10.
# virsh dumpxml rhel7.0-rhel |grep iothread
  <iothreads>1</iothreads>
  <iothreadids>
    <iothread id='2'/>
  </iothreadids>
    <iothreadpin iothread='2' cpuset='1'/>

Comment 6 errata-xmlrpc 2015-11-19 06:30:06 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://rhn.redhat.com/errata/RHBA-2015-2202.html