Bug 673111

Summary:	VDSM event loop can deadlock due to blocked write
Product:	Red Hat Enterprise Linux 6	Reporter:	Daniel Berrangé <berrange>
Component:	vdsm	Assignee:	Dan Kenigsberg <danken>
Status:	CLOSED CURRENTRELEASE	QA Contact:	yeylon <yeylon>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.1	CC:	abaron, bazulay, danken, hateya, iheim, srevivo
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	vdsm-4.9-47	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2011-08-19 15:13:25 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:

Description Daniel Berrangé 2011-01-27 13:28:32 UTC

Description of problem:
There is a flaw in the libvirt python demo program for events which can lead to a deadlock:
 
  http://www.redhat.com/archives/libvir-list/2011-January/msg00921.html

VDSM has a copy of this code as libvirtev.py and so should apply this same fix too.

Version-Release number of selected component (if applicable):
vdsm-4.9-12.2.x86_64

How reproducible:
Non-deterministically

Steps to Reproduce:
1.
2.
3.
  
Actual results:


Expected results:


Additional info:

Comment 1 Daniel Berrangé 2011-01-27 13:30:10 UTC

Opps, wrong hyperlink. This is the correct one

http://www.redhat.com/archives/libvir-list/2011-January/msg01131.html

Comment 3 Haim 2011-02-08 17:36:53 UTC

after talking to Dan, verified the bug as follows:

- started about 30 vms 
- killed all vms using pkill 
- all qemu processes died after a seconds

[root@rhev-i32c-01 tmp]# pgrep qemu
6902
16297
47818
65964
66246
66435
66817
67058
67451
67779
68109
68419
68849
69090
69495
69941
70242
[root@rhev-i32c-01 tmp]# pkill qemu
[root@rhev-i32c-01 tmp]# pgrep qemu
47818
68849
69090
69941
70242
[root@rhev-i32c-01 tmp]# pgrep qemu

vdsm-4.9-47.el6.x86_64