kernel panics with BUG

[Wren Turkal]

I have a Dell Sputnik 3 that I just got and upgraded it to 12.10->13.04->13.10. On boot the kernel crashes with a BUG. Attached is a dmesg output from after the loading of the module.

WORKAROUND: I can prevent the crash by blacklisting the iwlwifi module and I can cause the BUG by manually loading the module.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1263219

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Wren Turkal (wt-penguintechs-org)]

Here is the dmesg output.

This info is a little tricky to collect since I can't bring up my network (or shutdown my computer normally) after the BUG occurs. I have to boot into a 13.04 kernel to actually post this info. :) Does the apport store the output locally somewhere that will survive a reboot?

[Joseph Salisbury (jsalisbury)]

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v3.13 kernel[0].

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'.
Once testing of the upstream kernel is complete, please mark this bug as "Confirmed".

Thanks in advance.

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.13-rc3-trusty/

[Wren Turkal (wt-penguintechs-org)]

Sorry for the delay...holidays and all. I installed version 3.13.0-031300rc6-generic, which is beyond what was listed above. I hope that is okay. Everything seems to work just fine in this kernel. No panics and no BUGS during boot. Dmesg is also clean.

[penalvch (penalvch)]

Warren Turkal, thank you for performing the requested test. Could you please confirm this issue exists with the latest development release of Ubuntu? ISO images are available from http://cdimage.ubuntu.com/daily-live/current/ . If the issue remains, could you please engage your WORKAROUND, and attach your apport-collect file following https://help.ubuntu.com/community/ReportingBugs#Filing_bugs_when_off-line ?

[Wren Turkal (wt-penguintechs-org)]

FTR, here's the kernel version that's failing to boot:

$ dpkg -s linux-generic | grep Version
Version: 3.11.0.14.15

I see a number of other kernels associated with saucy in the list at http://kernel.ubuntu.com/~kernel-ppa/mainline/. Are there updates that haven't made it to saucy yet?

[Kent Baxley (kentb)]

@Warren,

What they're suggesting by development release is downloading the latest iso for 14.04 and trying it as well. Those kernels are (I think) still on version 3.12 instead of the release-candidate 3.13 ones. I believe the idea is that if the problem is fixed in 3.12-based kernels it'll probably help narrow things down a bit.

[Joseph Salisbury (jsalisbury)]

@Warren,

Thanks for testing the mainline kernel. It is good news that the bug does not exist 3.13-rc6. The next step is to see if the fix was already sent to stable and made it into the latest 3.11 kernel tree. The current Saucy kernel is version 3.11.0-15.22. Can you apply the latest updates to get to that kernel version and see if the bug still exists? If it does still exist, we can perform a reverse kernel bisect to find the commit in v3.13-rc6 that fixes this bug.

Thanks in advance!

[Wren Turkal (wt-penguintechs-org)]

FWIW, a new issue has cropped up with the new kernel. It looks like my touchpad disappears after resume from suspend for the night.

[Wren Turkal (wt-penguintechs-org)]

Well, I see the touchpad in the xinput list. It's just that the options for the touchpad are gone in the System Settings.

[penalvch (penalvch)]

Warren Turkal, thank you for your comments. Suspend is not scoped within this report, and is treated as a separate problem, necessitating a separate report. Hence, let us put the focus on suspend on hold for now, and we may circle back on that after your original issue "kernel panics with BUG" is Fix Released.

[Wren Turkal (wt-penguintechs-org)]

Is there a bug for the suspend? I have additional information I don't want to pollute this bug with.

[Wren Turkal (wt-penguintechs-org)]

For the record, the problem doesn't to be related to resuming after suspend, I have the same touchpad problem after reboot with the new kernel.

[Wren Turkal (wt-penguintechs-org)]

Filed new bug: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1265885

[Wren Turkal (wt-penguintechs-org)]

This kernel BUG does not occur on kernel version 3.12.6-031206-generic.

[penalvch (penalvch)]

Warren Turkal, thank you for testing the latest mainline kernel. The next step is to fully reverse commit bisect in order to identify the fix commit. Could you please do this following https://wiki.ubuntu.com/Kernel/KernelBisection ?

[Joseph Salisbury (jsalisbury)]

Were you able to test the latest Saucy kernel, which is version 3.11.0-15.22?

[Wren Turkal (wt-penguintechs-org)]

@jsalisbury, I only see 15.16...where do I get that one from?

@Christopher. I'll see what I can do as this is my work laptop.

[Wren Turkal (wt-penguintechs-org)]

FTR, there is a crash with 3.11.0-15.16. It looked different though. It happened after I saw the message about searching for Btrfs filesystemss. I don't have any more info at this time. I want to try the 3.11.0-15.22 kernel and maybe the latest trusty kernels. Where do I find them?

[Wren Turkal (wt-penguintechs-org)]

Okay, so I found 3.11.0-15.23. Is that the one you'd like me to test at this time?

I found it: at http://archive.ubuntu.com/ubuntu/ubuntu/pool/main/l/linux/linux-image-3.11.0-15-generic_3.11.0-15.23_amd64.deb

[penalvch (penalvch)]

Warren Turkal, one may test the latest Ubuntu kernel via live environment -> http://cdimage.ubuntu.com/daily-live/current/ .

[Wren Turkal (wt-penguintechs-org)]

Okay. I loaded the trusty linux-image+extras (3.12.0-8-generic) into saucy. There are no problems with wifi in this version. Dmesg is clean.

[Joseph Salisbury (jsalisbury)]

We can perform a reverse bisect to identify the fix for this bug in 3.13-rc6. However, we also need to bisect bug 1265885 . Do you want to revers bisect this bug or bisect bug 1265885 first?

[Wren Turkal (wt-penguintechs-org)]

I am sorry. I have been extremely busy these past couple weeks. I'll try to make some progress soon.

[Wren Turkal (wt-penguintechs-org)]

Here's another data point as I just tried another of the generic kernels. Version "3.12.0-031200-generic #201311071835" has no problems with the iwlwifi AFAICT.

[Wren Turkal (wt-penguintechs-org)]

The version "3.13.1-031301-generic" also seems to work without issues.

[Wren Turkal (wt-penguintechs-org)]

Work with regard to the iwlwifi module, that is.

[Wren Turkal (wt-penguintechs-org)]

The iwlwifi module works fine with a kernel based on Linus' tree that I compiled this morning.

[Wren Turkal (wt-penguintechs-org)]

I am just curious. Is saucy going to be updated? It might be a shocker to someone when they can't get a network connection on saucy?

[Joseph Salisbury (jsalisbury)]

Saucy will be updated to what is now in the proposed repository. That might actually be a good test, to see if proposed also exhibits this bug. The proposed kernel has the updates from upstream 3.11.10.3, which include some iwlwifi fixes.

See https://wiki.ubuntu.com/Testing/EnableProposed for documentation how to enable and use -proposed.

[Wren Turkal (wt-penguintechs-org)]

The latest proposed kernel fails even worse than my original report. The conditions when it fails (that is when the iwlwifi module is loaded) is the same. However, now blacklisting iwlwifi and then manually modprobing it after logging in locks up the system such that I cannot capture the dmesg. Before, I was able to capture dmesg after attempting to load the module.

FWIW, I also compiled a 3.14-rc2 kernel. It doesn't have this problem.

[Wren Turkal (wt-penguintechs-org)]

Okay, I am booted into the kernel @http://kernel.ubuntu.com/~kernel-ppa/mainline/v3.11-saucy/. It works just fine. This seems to be a mainline 3.11 kernel. Does that help close the gap for where the problem showed up?

[penalvch (penalvch)]

Warren Turkal, could you please boot into a prior working release (live or installed), and execute the following in a terminal:
apport-collect 1263219

[Launchpad Janitor (janitor)]

[Expired for linux (Ubuntu) because there has been no activity for 60 days.]

[Wren Turkal (wt-penguintechs-org)]

This bug doesn't appear to exist in the new Trusty release.

[penalvch (penalvch)]

As per https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1263219/comments/35 .