Bug 630129

Summary: [RHEL5 IA64 XEN] netfront driver: alloc_dev: Private data too big.
Product: Red Hat Enterprise Linux 5 Reporter: Jarod Wilson <jarod>
Component: kernelAssignee: Neil Horman <nhorman>
Status: CLOSED ERRATA QA Contact: Boris Ranto <branto>
Severity: medium Docs Contact:
Priority: urgent    
Version: 5.6CC: branto, dhoward, drjones, jburke, jmarchan, jpirko, jwest
Target Milestone: rcKeywords: ZStream
Target Release: ---   
Hardware: ia64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Recently applied patch introduced a bug, which caused the Xen guest networking not to work properly on 64-bit Itanium processors. However, this bug also revealed an issue, which may have led to a data corruption. With this update, both errors have been fixed, and Xen virtual guest networking now works as expected.
 Story Points: ---
Clone Of:
: 630163 (view as bug list) Environment:
Last Closed: 2011-01-13 21:15:40 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: 630163, 637219, 637220    
Attachments:
Description Flags
utested patch
none
tested patch none

Description Jarod Wilson 2010-09-03 18:44:18 UTC 
Description of problem:
Since the inclusion of the patch for bug 620508, ia64 xen guest networking fails to function. However, this is probably a good thing, since it would appears that its historically been silently corrupting data.

Version-Release number of selected component (if applicable):
2.6.18-215.el5xen.ia64

How reproducible:
Install ia64 xen guest, update to 2.6.18-215.el5xen

Log snippets from 214 and 215 kernels:

Sep  3 12:55:05 dhcp71-32 kernel: Linux version 2.6.18-214.el5xen (mockbuild.redhat.com) (gcc version 4.1.2        20080704 (Red Hat 4.1.2-48)) #1 SMP Fri Aug 27 18:15:55 EDT 2010
...
Sep  3 12:55:09 dhcp71-32 kernel: netfront: Initialising virtual ethernet driver.
Sep  3 12:55:09 dhcp71-32 kernel: netfront: device eth0 has flipping receive path.


Sep  3 13:57:19 dhcp71-32 kernel: Linux version 2.6.18-215.el5.testxen (root.eng.bos.redhat.com) (gcc version 4.1.2    20080704 (Red Hat 4.1.2-48)) #1 SMP Fri Sep 3 12:17:32 EDT 2010
...
Sep  3 13:57:24 dhcp71-32 kernel: netfront: Initialising virtual ethernet driver.
Sep  3 13:57:24 dhcp71-32 kernel: alloc_dev: Private data too big.
Sep  3 13:57:24 dhcp71-32 kernel: create_netdev> alloc_etherdev failed.
Sep  3 13:57:24 dhcp71-32 kernel: vif vif-0: 12 creating netdev
Sep  3 13:57:24 dhcp71-32 kernel: vif vif-0: 12 xenbus_dev_probe on device/vif/0
Comment 1 Jarod Wilson 2010-09-03 18:51:05 UTC 
Adding Drew to the cc list so he's aware of this one too.
Comment 2 Jarod Wilson 2010-09-03 18:52:16 UTC 
Since its a data corruptor, its likely we're going to want it for z-stream as well, so also adding z-stream folks to cc list.
Comment 3 Neil Horman 2010-09-03 20:12:45 UTC 
Created attachment 442975 [details]
utested patch

Still need to test it, but heres my first pass at a patch to fix this.  Basically just allocate a wrapper struct as the netdev_private data, which contains a pointer to the separately allocated netfront_info struct that is more than 65kb long.  Should do the trick.  Will test it out ASAP.
Comment 5 RHEL Program Management 2010-09-03 20:59:11 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 6 Jerome Marchand 2010-09-08 15:19:31 UTC 
(In reply to comment #3)
> Created attachment 442975 [details]
> utested patch
> 
> Still need to test it, but heres my first pass at a patch to fix this. 
> Basically just allocate a wrapper struct as the netdev_private data, which
> contains a pointer to the separately allocated netfront_info struct that is
> more than 65kb long.  Should do the trick.  Will test it out ASAP.

Your patch should set err = -ENOMEM. The ERR_PTR() cast is already made when we return from the function.
Actually, since the only error it can return is -ENOMEM, we can get rid of err variable and ERR_PTR(-ENOMEM) all the time.
Comment 7 Neil Horman 2010-09-08 20:46:21 UTC 
Created attachment 446082 [details]
tested patch

heres a version of the patch that I've tested and validated, and a brew build of it.  I'll post it shortly

http://brewweb.devel.redhat.com/brew/taskinfo?taskID=2750022
Comment 10 Jarod Wilson 2010-09-10 21:41:21 UTC 
in kernel-2.6.18-219.el5
You can download this test kernel from http://people.redhat.com/jwilson/el5

Detailed testing feedback is always welcomed.
Comment 15 Jaromir Hradilek 2010-10-12 22:51:42 UTC 
    Technical note added. If any revisions are required, please edit the "Technical Notes" field
    accordingly. All revisions will be proofread by the Engineering Content Services team.
    
    New Contents:
Recently applied patch introduced a bug, which caused the Xen guest networking not to work properly on 64-bit Itanium processors. However, this bug also revealed an issue, which may have led to a data corruption. With this update, both errors have been fixed, and Xen virtual guest networking now works as expected.
Comment 18 errata-xmlrpc 2011-01-13 21:15:40 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-2011-0017.html