Bug 611838

Summary:	powering down guest causes network connection problem with host for 20-50 seconds
Product:	Red Hat Enterprise Linux 5	Reporter:	olaf
Component:	libvirt	Assignee:	Daniel Veillard <veillard>
Status:	CLOSED DUPLICATE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	high	Docs Contact:
Priority:	low
Version:	5.5	CC:	berrange, eblake, mkenneth, virt-maint, xen-maint, ykaul
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2010-07-13 12:05:31 UTC	Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:
Bug Blocks:	580948

Description olaf 2010-07-06 15:54:48 UTC

Description of problem:
When I power down a guest in virt-manager then I cannot connect to the host machine for 20-50 seconds.
The guests are connected using bridged networking.

Version-Release number of selected component (if applicable):
kvm-83-164.12
kmod-kvm-83-164.12
kernel-2.6.18-194.8.1.el5

Host OS: CentOS 5.5, x86_64
Guest OS: CentOS 5.4, Windows XP

How reproducible:
Always

Steps to Reproduce:
Create and install a guest with bridged networking. Next power down the guest OS.

  
Actual results:
The current connections to host are broken and it is even impossible to ping the host for 20-50 seconds.

Expected results:
No impact on host networking.

Additional info:

Here are described similar problems in Debian and Ubuntu:

http://kerneltrap.org/mailarchive/linux-kvm/2010/4/21/6261001/thread

https://bugs.launchpad.net/ubuntu/+source/qemu-kvm/+bug/584048

In /var/log/messages I see:
Jul  6 17:21:39 daisy kernel: br0: port 2(vnet0) entering disabled state
Jul  6 17:21:39 daisy kernel: device vnet0 left promiscuous mode
Jul  6 17:21:39 daisy kernel: br0: port 2(vnet0) entering disabled state

Comment 1 olaf 2010-07-12 15:07:16 UTC

It seems that probable cause is described in bug #571991

Comment 2 olaf 2010-07-12 19:53:30 UTC

I was able to fix this problem applying patch from bug #571991

Comment 3 Michael S. Tsirkin 2010-07-13 11:36:15 UTC

The issue here that somehow, tun got to be the first interface on the bridge.
So bridge gets the mac from tun, when we disconnect
this tun mac changes.
In addition to the patch suggested, we could connect eth0 first, and
this issue will go away.

Since libvirt does the bridge setup, this needs to be fixed there.
Changing component appropriately.

Comment 4 Daniel Berrangé 2010-07-13 12:05:31 UTC


*** This bug has been marked as a duplicate of bug 571991 ***