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Bug 1088165 - libvirtd crashed after hot-unplug the vcpus which is pined to host cpus
Summary: libvirtd crashed after hot-unplug the vcpus which is pined to host cpus
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: libvirt
Version: 6.6
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: ---
Assignee: Ján Tomko
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks: 1091206
TreeView+ depends on / blocked
 
Reported: 2014-04-16 07:34 UTC by Xuesong Zhang
Modified: 2016-04-26 14:41 UTC (History)
9 users (show)

Fixed In Version: libvirt-0.10.2-34.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2014-10-14 04:21:16 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)
libvirt crashed bt info (9.38 KB, text/plain)
2014-04-16 07:35 UTC, Xuesong Zhang 		no flags Details
View All


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2014:1374 0 normal SHIPPED_LIVE libvirt bug fix and enhancement update 2014-10-14 08:11:54 UTC

Description Xuesong Zhang 2014-04-16 07:34:25 UTC 
Description of problem:
libvirtd crashed after hot-unplug the vcpus which is pined to some host cpus.

Version-Release number of selected component (if applicable):
libvirt-0.10.2-32.el6.x86_64
qemu-kvm-rhev-0.12.1.2-2.423.el6.x86_64
kernel-2.6.32-457.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1. prepare one shutoff guest, revise the dumpxml as following:
......
  <vcpu placement='static' current='2'>4</vcpu>
......

2. start the guest

3. check the cpu settings in the dumpxml
# virsh dumpxml rhel6.5|grep cpu
  <vcpu placement='static' current='2'>4</vcpu>

4. pin the 2nd cpu to some host cpus.
# virsh vcpupin rhel6.5 1 0,3

5. check the cpu settings in the dumpxml again, the result is as expected.
# virsh dumpxml rhel6.5|grep cpu
  <vcpu placement='static' current='2'>4</vcpu>
  <cputune>
    <vcpupin vcpu='1' cpuset='0,3'/>
  </cputune>


6. hot-unplug the vcpus
# virsh setvcpus rhel6.5 1


7. check the cpu settings in the dumpxml again, then libvirtd dead.
# virsh dumpxml rhel6.5|grep cpu
error: Failed to reconnect to the hypervisor
error: no valid connection
error: Failed to connect socket to '/var/run/libvirt/libvirt-sock': Connection refused

# service libvirtd status
libvirtd dead but pid file exists




Actual results:
As step 7

Expected results:
libvirt should not crashed, should prompt the user the hot-unplug cpus are pined to host cpus and forbid to hot-unplug it.


Addtional info:
attached is the bt info for reference.
Comment 1 Xuesong Zhang 2014-04-16 07:35:49 UTC 
Created attachment 886775 [details]
libvirt crashed bt info
Comment 2 Ján Tomko 2014-04-22 12:54:04 UTC 
Patch posted upstream:
https://www.redhat.com/archives/libvir-list/2014-April/msg00825.html
Comment 3 Ján Tomko 2014-04-22 14:50:46 UTC 
Now pushed upstream:
commit a0a8dc695e9e20fa8b4ebe9c7ad697a4e9b3ac41
Author:     Ján Tomko <jtomko>
CommitDate: 2014-04-22 14:49:25 +0200

    Properly free vcpupin info for unplugged CPUs
    
    Remove the pointer from def->cputune.vcpupin after unplugging
    the CPU and also free the bitmap contained in the structure
    by calling virDomainVcpuPinDel instead of VIR_FREE.
    
    Introduced by commit 0df1a79.
    
    This makes virDomainLookupVcpuPin redundant.
    
    https://bugzilla.redhat.com/show_bug.cgi?id=1088165
                                 
git describe: v1.2.3-144-ga0a8dc6

Posted downstream:
http://post-office.corp.redhat.com/archives/rhvirt-patches/2014-April/msg00455.html
Comment 6 Jincheng Miao 2014-05-04 08:05:44 UTC 
The latest libvirt-0.10.2-34.el6 will not crash after hot-unplug the vcpu which is pined.

# virsh start r6
Domain r6 started

# virsh vcpupin r6
VCPU: CPU Affinity
----------------------------------
   0: 0-7
   1: 0-7

# virsh vcpupin r6 1 0,3

# virsh dumpxml r6 | grep cputune
  <cputune>
  </cputune>

# virsh dumpxml r6 | grep -1 cputune
  <vcpu placement='static' current='2'>4</vcpu>
  <cputune>
    <vcpupin vcpu='1' cpuset='0,3'/>
  </cputune>
  <os>

# virsh setvcpus r6 1

# service libvirtd status
libvirtd (pid  7850) is running...
Comment 8 errata-xmlrpc 2014-10-14 04:21:16 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.

http://rhn.redhat.com/errata/RHBA-2014-1374.html
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