Bug 487691

Summary: [RHEL5.3]: modprobe xen-vnif in a KVM guest causes a crash
Product: Red Hat Enterprise Linux 5 Reporter: Chris Lalancette <clalance>
Component: kernelAssignee: Chris Lalancette <clalance>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: low    
Version: 5.3CC: dzickus, jbao, qcai, xen-maint
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2009-09-02 08:55:06 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:
Attachments:
Description Flags
Full crash output
none
Patch to unregister things properly when failing a modprobe none

Description Chris Lalancette 2009-02-27 14:28:02 UTC 
Description of problem:
This BZ is sort of a corollary to the RHEL-4 BZ 485421.  However, while they are related, they are not exactly the same.  If you have a RHEL-5.3 kernel running as a KVM guest, and you try to "modprobe xen-vnif" inside the guest, you get:

FATAL: Error inserting xen_vnif (/lib/modules/2.6.18-132.el5virttest10/kernel/drivers/xenpv_hvm/netfront/xen-vnif.ko): No such device

Which is the correct behavior.  However, if you then try to shut down that guest, you will get a crash when the guest is trying to turn off the network interfaces, like this:

Shutting down interface eth0:  BUG: unable to handle kernel paging request at virtual address f0a7e3e4

(the rest of the crash is in the attachment).  This should clearly be fixed.
Comment 1 Chris Lalancette 2009-02-27 14:29:21 UTC 
Created attachment 333475 [details]
Full crash output
Comment 2 Chris Lalancette 2009-02-27 17:44:59 UTC 
Created attachment 333512 [details]
Patch to unregister things properly when failing a modprobe

This patch seems to fix the problem reported in this BZ.  It's actually a combination of the "rest" of upstream xen-unstable c/s 14622 (we have the other parts of that c/s), plus some custom code that I've now sent upstream.  With this in place, the crash no longer happens on shutdown.
Comment 4 RHEL Program Management 2009-02-27 18:21:26 UTC 
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update
release.
Comment 11 errata-xmlrpc 2009-09-02 08:55:06 UTC 
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.

http://rhn.redhat.com/errata/RHSA-2009-1243.html