Bug 844582

Summary:	virtio-rng: module removal doesn't succeed till input from host received
Product:	Red Hat Enterprise Linux 6	Reporter:	Amit Shah <amit.shah>
Component:	kernel	Assignee:	Amit Shah <amit.shah>
Status:	CLOSED ERRATA	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	6.4	CC:	areis, juzhang, mdeng, michen, qzhang, rhod, shuang, virt-maint
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	kernel-2.6.32-298.el6	Doc Type:	Bug Fix
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2013-02-21 06:44:15 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 Amit Shah 2012-07-31 06:21:59 UTC

Description of problem:

If input from host is expected (e.g. by executing cat /dev/hwrng), and module removal is attempted, the rmmod process doesn't finish.

The fix is to not wait for host input when module remove request is received.
Upstream commit is 4476987a9a4525db3ebe29538cc357ca589db4ac.

For testing this, the virtio-rng device isn't yet available upstream or in a RHEL release.  I can give a qemu-kvm build to QE for testing and verification purposes, let me know when you need it.

Comment 1 RHEL Program Management 2012-08-06 10:11:30 UTC

This request was evaluated by Red Hat Product Management for
inclusion in a Red Hat Enterprise Linux release.  Product
Management has requested further review of this request by
Red Hat Engineering, for potential inclusion in a Red Hat
Enterprise Linux release for currently deployed products.
This request is not yet committed for inclusion in a release.

Comment 2 juzhang 2012-08-09 02:51:38 UTC

marked ack+, qe tried virtio rng build.

Comment 4 Jarod Wilson 2012-08-16 15:01:10 UTC

Patch(es) available on kernel-2.6.32-298.el6

Comment 7 Qunfang Zhang 2012-12-28 08:10:17 UTC

Hi, Amit
Tested on both kernel-2.6.32-279.el6 and kernel-2.6.32-348.el6 and the issues seems still exist. 

Steps:

1. Build a upstream qemu-kvm that has virtio-rng-pci device.

2. Boot a rhel6.3/rhel6.4 guest with "-device virtio-rng-pci,bus=pci.0,addr=0xa,id=rng0".

3. # lsmod | grep virtio
virtio_rng              2752  0 
......
virtio_ring             8301  5 virtio_rng,virtio_balloon,virtio_console,virtio_net,virtio_pci
virtio                  4977  5 virtio_rng,virtio_balloon,virtio_console,virtio_net,virtio_pci

4. #cat /dev/hwrng 

5. #rmmod virtio_rng

Result: After step 5, the 'rmmod' can not finished. Test both kernel-2.6.32-279.el6 and kernel-2.6.32-348.el6.

Hi, Amit
Could you help have a look?  Is there something wrong with my steps or the patch is not getting in so something else? 


Thanks,
Qunfang

Comment 8 Qunfang Zhang 2013-01-07 07:50:23 UTC

Hi, Amit
I re-assign this bug as still have problem. Please take a look at it and correct me if there's some wrong.

Thanks,
Qunfang

Comment 12 errata-xmlrpc 2013-02-21 06:44:15 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/RHSA-2013-0496.html