Occasional kernel panic on shutdown in ext4 code (dquot_drop)

[Maik Merten]

Occasionally (about once every three weeks) my machine experiences a kernel panic somewhere in the ext4 code on shutdown (and only on shutdown).

Ubuntu Version: 18.04, x86-64

Platform: AMD Ryzen R7 2700 on an Asrock AB350M-Pro4 mainboard.

I attached two photos of the panic messages, one occurring on May 16th, the other on June 26th. The call trace is identical in both.

Given how similar the messages are, I don't think this is an intermittent machine-related glitch. As of yet, however, I could not identify a pattern on when the issue occurs.

Kernel versions:
 - May 16th: 4.15.0-20-generic
 - June 26th: 4.15.0-23-generic
---
ProblemType: Bug
ApportVersion: 2.20.9-0ubuntu7.2
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC2: maik 1743 F.... pulseaudio
 /dev/snd/controlC1: maik 1743 F.... pulseaudio
 /dev/snd/controlC0: maik 1743 F.... pulseaudio
CurrentDesktop: GNOME
DistroRelease: Ubuntu 18.04
HibernationDevice: RESUME=UUID=a4be9bd2-a879-438d-be59-41d095ad18fb
InstallationDate: Installed on 2017-08-25 (306 days ago)
InstallationMedia: Ubuntu-GNOME 17.04 "Zesty Zapus" - Release amd64 (20170412)
MachineType: To Be Filled By O.E.M. To Be Filled By O.E.M.
Package: linux (not installed)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=de_DE.UTF-8
 SHELL=/bin/bash
ProcFB: 0 amdgpudrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-23-generic root=UUID=20c38f5a-e4d2-4cee-9daa-84a848f15452 ro quiet splash vt.handoff=1
ProcVersionSignature: Ubuntu 4.15.0-23.25-generic 4.15.18
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-23-generic N/A
 linux-backports-modules-4.15.0-23-generic N/A
 linux-firmware 1.173.1
RfKill:
 0: phy0: Wireless LAN
  Soft blocked: no
  Hard blocked: no
Tags: bionic
Uname: Linux 4.15.0-23-generic x86_64
UpgradeStatus: Upgraded to bionic on 2018-04-26 (62 days ago)
UserGroups: adm cdrom dialout dip lpadmin plugdev sambashare sudo
_MarkForUpload: True
dmi.bios.date: 05/08/2018
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: L4.82
dmi.board.name: AB350M Pro4
dmi.board.vendor: ASRock
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrL4.82:bd05/08/2018:svnToBeFilledByO.E.M.:pnToBeFilledByO.E.M.:pvrToBeFilledByO.E.M.:rvnASRock:rnAB350MPro4:rvr:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.family: To Be Filled By O.E.M.
dmi.product.name: To Be Filled By O.E.M.
dmi.product.version: To Be Filled By O.E.M.
dmi.sys.vendor: To Be Filled By O.E.M.

[Maik Merten (maikmerten)]

(add the second attachment)

[Ubuntu Foundations Team Bug Bot (crichton)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It seems that your bug report is not filed about a specific source package though, rather it is just filed against Ubuntu in general. It is important that bug reports be filed about source packages so that people interested in the package can find the bugs about it. You can find some hints about determining what package your bug might be about at https://wiki.ubuntu.com/Bugs/FindRightPackage. You might also ask for help in the #ubuntu-bugs irc channel on Freenode.

To change the source package that this bug is filed about visit https://bugs.launchpad.net/ubuntu/+bug/1779063/+editstatus and add the package name in the text box next to the word Package.

[This is an automated message. I apologize if it reached you inappropriately; please just reply to this message indicating so.]

[Maik Merten (maikmerten)]

add "linux" as affected package.

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:

apport-collect 1779063

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.

[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Maik Merten (maikmerten)]

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[Joseph Salisbury (jsalisbury)]

Did this issue start happening after an update/upgrade? Was there a prior kernel version where you were not having this particular problem?

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.18 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'.

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/v4.18-rc2

[Maik Merten (maikmerten)]

The issue started after upgrading from 17.10 to 18.04. However, at the same time I also upgraded the CPU from an AMD A12-9800 to the AMD Ryzen 7 2700 (with the rest of the system remaining unchanged). I don't have the older CPU anymore, so I cannot change back for test purposes. Given the documented occurrences produced exactly the same call trace I don't expect this to be an intermittent CPU problem (e.g., causes by a CPU errata).

I can certainly try an upstream kernel. Sadly the issue occurs only on rare occasions, so it may take quite a while to be reasonably sure things are okay.

[Maik Merten (maikmerten)]

It seems one of the RAM modules in that machine degraded over time - while memtest86 found no problems in the past, now errors are discovered within seconds.

It's unclear when the module became faulty, but it's quite plausible that the observed kernel panics were caused by this and that there's no actual software bug involved.

I'll replace the system RAM and revert back to the normal Ubuntu kernel. I think this issue can be closed - if the same symptoms reassert themselves, things can be revisited.