8086:0091 WARNING: at /home/apw/COD/linux/drivers/net/wireless/iwlwifi/iwl-trans.h:565 iwlagn_mac_flush+0x1a3/0x1b0 [iwlwifi]()

[Joe Talbott]

The kernel panics after using the hotkey to disable then re-enable the wifi card on a Dell XPS 14z.

ProblemType: Bug
DistroRelease: Ubuntu 12.10
Package: linux-image-3.5.0-6-generic 3.5.0-6.6
ProcVersionSignature: Ubuntu 3.5.0-6.6-generic 3.5.0
Uname: Linux 3.5.0-6-generic x86_64
ApportVersion: 2.4-0ubuntu5
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: josepht 1616 F.... pulseaudio
Date: Thu Jul 26 12:25:09 2012
HibernationDevice: RESUME=UUID=73391588-01f4-4d2c-bde4-7d7e0bbe2512
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20120307)
MachineType: Dell Inc. XPS L412Z
ProcEnviron:
 TERM=xterm
 PATH=(custom, user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 inteldrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.5.0-6-generic root=UUID=7711a507-5be1-4578-8929-5f182591e549 ro crashkernel=384M-2G:64M,2G-:128M quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.5.0-6-generic N/A
 linux-backports-modules-3.5.0-6-generic N/A
 linux-firmware 1.86
SourcePackage: linux
StagingDrivers: rts_pstor
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 11/15/2011
dmi.bios.vendor: Dell Inc.
dmi.bios.version: A03
dmi.board.name: 008DD8
dmi.board.vendor: Dell Inc.
dmi.board.version: A00
dmi.chassis.type: 8
dmi.chassis.vendor: Dell Inc.
dmi.chassis.version: A03
dmi.modalias: dmi:bvnDellInc.:bvrA03:bd11/15/2011:svnDellInc.:pnXPSL412Z:pvrA03:rvnDellInc.:rn008DD8:rvrA00:cvnDellInc.:ct8:cvrA03:
dmi.product.name: XPS L412Z
dmi.product.version: A03
dmi.sys.vendor: Dell Inc.

[Joe Talbott (joetalbott)]

Kernel log

[Joe Talbott (joetalbott)]

picture of kernel stack trace.

[penalvch (penalvch)]

Joe Talbott, if you could also please test the latest upstream kernel available that would be great. It will allow additional upstream developers to examine the issue. Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please do not test the kernel in the daily folder, but the one all the way at the bottom. Once you've tested the upstream kernel, please remove the 'needs-upstream-testing' tag. This can be done by clicking on the yellow pencil icon next to the tag located at the bottom of the bug description and deleting the 'needs-upstream-testing' text. As well, please comment on which kernel version specifically you tested.

If this bug is fixed in the mainline kernel, please add the following tag 'kernel-fixed-upstream'.

If the mainline kernel does not fix this bug, please add the tag: 'kernel-bug-exists-upstream'.

If you are unable to test the mainline kernel, for example it will not boot, please add the tag: 'kernel-unable-to-test-upstream', and comment as to why specifically you were unable to test it.

Please let us know your results. Thanks in advance.

[Joe Talbott (joetalbott)]

I actually tested this on mainline 3.5.0 rc7 first and that kernel panics too.

linux-image-3.5.0-030500rc7-generic_3.5.0-030500rc7.201207142035_amd64.deb
linux-image-extra-3.5.0-030500rc7-generic_3.5.0-030500rc7.201207142035_amd64.deb

[penalvch (penalvch)]

Joe Talbott, thank you for testing the mainline. Did this problem occur for you in a prior version of Ubuntu?

[Joe Talbott (joetalbott)]

I can't say because I hadn't previously had to disable/enable the wifi card. I'll try installing Precise and see if it exists there as well.

[Joe Talbott (joetalbott)]

I just tried disabling/enabling the wifi card using last nights daily builds for Precise desktop amd64 and Quantal desktop amd64. The live session on the Precise iso does not exhibit this panic. The live session on the Quantal iso does exhibit this panic.

[penalvch (penalvch)]

Joe Talbott, thank you for testing for the problem and proving this is a regression. The next step is to perform a kernel bisect from Precise 3.2.0-23.36 to Quantal 3.5.0-6, in order to identify the offending commit(s). Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection ?

Helpful Bug Reporting Links:
https://help.ubuntu.com/community/ReportingBugs#Bug_Reporting_Etiquette
https://help.ubuntu.com/community/ReportingBugs#A3._Make_sure_the_bug_hasn.27t_already_been_reported
https://help.ubuntu.com/community/ReportingBugs#Adding_Apport_Debug_Information_to_an_Existing_Launchpad_Bug
https://help.ubuntu.com/community/ReportingBugs#Adding_Additional_Attachments_to_an_Existing_Launchpad_Bug

[Joe Talbott (joetalbott)]

Here's the mainline kernel bisection results

works: linux-image-3.4.6-030406-generic_3.4.6-030406.201207191609_amd64.deb
fails: linux-image-3.5.0-030500-generic_3.5.0-030500.201207211835_amd64.deb

[penalvch (penalvch)]

Joe Talbott, ok. Now that you have found the kernel version regressor and regressee, the next step is to bisect the commits between these two versions to find the offending commit(s). Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection#How_to_bisect_a_sequence_of_commits_to_find_the_bad_one ?

[Joe Talbott (joetalbott)]

The results of the commit bisection are:

dd551ab7b47ace14753b0d73f79437cc35adcf6b is the first bad commit
commit dd551ab7b47ace14753b0d73f79437cc35adcf6b
Author: Wey-Yi Guy <email address hidden>
Date: Thu May 3 14:22:01 2012 -0700

    iwlwifi: include rssi as part of decision making for reduce txpower

    In bt coex, consider the average rssi as part of decision making process

    Change-Id: I8d11d7f177a6875e2a9d08f7539d42253226fd7a
    Signed-off-by: Wey-Yi Guy <email address hidden>
    Reviewed-on: http://git-mwg.jer.intel.com/gerrit/1945
    Tested-by: Jenkins
    Reviewed-by: Emmanuel Grumbach <email address hidden>
    Signed-off-by: John W. Linville <email address hidden>

:040000 040000 c23ca441c567a6424b616cf936be68034864d06f 780c4965ae0945ae4908694e80602971d401195f M drivers

[penalvch (penalvch)]

Joe Talbott, thank you for commit bisecting. I'll mark this Triaged due to this and how the mainline was tested.

[Joseph Salisbury (jsalisbury)]

Hi Joe,

I built a test kernel with commit dd551ab7b47ace14753b0d73f79437cc35adcf6b reverted. The test kernel can be downloaded from:
http://people.canonical.com/~jsalisbury/lp1029547

Can you test that kernel and report back if it resolves the bug?

Thanks in advance!

[Joe Talbott (joetalbott)]

Hi Joseph,

The test kernel does resolve the bug.

Thanks,
Joe

[Joseph Salisbury (jsalisbury)]

Thanks for testing, Joe. I'll take a closer look at that commit and search if it's being addressed upstream.

[Joseph Salisbury (jsalisbury)]

Upstream duplicate: https://bugzilla.kernel.org/show_bug.cgi?id=45481

The fix has been sent to stable:

http://<email address hidden>/msg12286.html

[Joseph Salisbury (jsalisbury)]

I created a Quantal test kernel with commit e19ebcab01cc130fa832764d453b263460ec3b91 backported from v3.6-rc1.

This kernel is available from:
http://people.canonical.com/~jsalisbury/lp1029547

Can you test that kernel and report back if it fixes this bug or not?