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 844579 - virtio-rng: 'cat' process hangs when ^C pressed when there's no input
Summary: virtio-rng: 'cat' process hangs when ^C pressed when there's no input
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 6
Classification: Red Hat
Component: kernel
Version: 6.4
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Amit Shah
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2012-07-31 06:16 UTC by Amit Shah
Modified: 2013-02-21 06:44 UTC (History)
7 users (show)

Fixed In Version: kernel-2.6.32-298.el6
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2013-02-21 06:44:11 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Bugzilla 849196 1 None None None 2021-01-20 06:05:38 UTC
Red Hat Product Errata RHSA-2013:0496 0 normal SHIPPED_LIVE Important: Red Hat Enterprise Linux 6 kernel update 2013-02-20 21:40:54 UTC

Internal Links: 849196

Description Amit Shah 2012-07-31 06:16:48 UTC 
Description of problem:

When the host doesn't provide the virtio-rng driver with any data, this set of commands just hangs:

# cat /dev/hwrng
^C

Instead of using wait_for_completion(), use wait_for_completion_killable() to ensure the read is killable.

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 Amit Shah 2012-07-31 06:21:26 UTC 
Upstream commit with fix is cc8744e12936680478ce82b0f21dbaa272df1447
Comment 2 RHEL Program Management 2012-08-06 10:11:36 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 3 juzhang 2012-08-09 02:56:28 UTC 
qe will verify this bug along with bz844583/844582/786407
Comment 5 Jarod Wilson 2012-08-16 15:01:01 UTC 
Patch(es) available on kernel-2.6.32-298.el6
Comment 8 Qunfang Zhang 2012-12-27 05:21:08 UTC 
Hi, Amit
We want to verify the virt-rng related bugs in kernel component but seems virtio-rng device is still not available in qemu-kvm official build? 
BTW, do we have a qemu-kvm bug to track it?
Comment 10 Qunfang Zhang 2012-12-28 07:00:34 UTC 
Hi Amit
I tried to reproduce the issue with kernel-279 installed in guest.

Steps:
0. I'm using the upstream qemu-kvm because currently neither rhel6 nor rhel7 has virtio-rng device.

1. Boot guest with  "-device virtio-rng-pci,bus=pci.0,addr=0xa,id=rng0"

2. After guest boot up. 
(1)#cat /etc/hwrng
(2)"Ctrl+c" to kill the above command.

Result: In a rhel6.3 guest kernel (kernel-279), the command hangs for a while, about 5 to 10 seconds. But at last the command is killed. 

And then I verified this issue with a rhel6.4 guest (kernel-348). 

Result: After step 2.(2), the command could be killed immediately. 

Amit,
Is this the reproduction phenomenon in the older kernel-279?  It is not always hang, but only for some seconds.

Thanks,
Qunfang
Comment 11 Qunfang Zhang 2012-12-28 07:44:04 UTC 
I think this can be verified pass with the following steps:

1. Boot guest with  "-device virtio-rng-pci,bus=pci.0,addr=0xa,id=rng0"

2. Inside guest:
#cat /dev/hwrng

3. #pm-suspend

4. Resume guest.

5. Using "Ctrl+c" to kill the command in step 2. 

Result:
In the old kernel-2.6.32-279.el6.x86_64, the command can not be killed. 
In the newer kernel-2.6.32-348.el6.x86_64, the command can be killed immediately.

So based on comment 10 and comment 11, this bug can be verified.
Comment 12 Amit Shah 2013-01-02 11:47:07 UTC 
Steps in comment 10 and 11 look correct.  Thanks.
Comment 14 errata-xmlrpc 2013-02-21 06:44:11 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
Note You need to log in before you can comment on or make changes to this bug.