Panic during SyS_reboot

[Knickers Brown]

BUG: unable to handle kernel NULL pointer dereference at (null)
IP: device_shutdown+0xbb/0x200
PGD 0 P4D 0
Oops: 0002 [#1] SMP NOPTI

See the screenshot for more.

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: linux-image-4.15.0-12-generic 4.15.0-12.13
ProcVersionSignature: Ubuntu 4.15.0-12.13-generic 4.15.7
Uname: Linux 4.15.0-12-generic x86_64
ApportVersion: 2.20.8-0ubuntu10
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: ksta 1624 F.... pulseaudio
 /dev/snd/controlC2: ksta 1624 F.... pulseaudio
 /dev/snd/controlC1: ksta 1624 F.... pulseaudio
CurrentDesktop: ubuntu:GNOME
Date: Fri Mar 23 07:01:58 2018
InstallationDate: Installed on 2018-03-13 (9 days ago)
InstallationMedia: Ubuntu 18.04 LTS "Bionic Beaver" - Alpha amd64 (20180311)
MachineType: Gigabyte Technology Co., Ltd. AX370-Gaming 5
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 nouveaufb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-12-generic root=UUID=5a435321-b09d-44ad-a2ca-cfda4521071d ro quiet splash vt.handoff=1
RelatedPackageVersions:
 linux-restricted-modules-4.15.0-12-generic N/A
 linux-backports-modules-4.15.0-12-generic N/A
 linux-firmware 1.173
RfKill:

SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 02/13/2018
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F22b
dmi.board.asset.tag: Default string
dmi.board.name: AX370-Gaming 5
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: Default string
dmi.chassis.asset.tag: Default string
dmi.chassis.type: 3
dmi.chassis.vendor: Default string
dmi.chassis.version: Default string
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF22b:bd02/13/2018:svnGigabyteTechnologyCo.,Ltd.:pnAX370-Gaming5:pvrDefaultstring:rvnGigabyteTechnologyCo.,Ltd.:rnAX370-Gaming5:rvrDefaultstring:cvnDefaultstring:ct3:cvrDefaultstring:
dmi.product.family: Default string
dmi.product.name: AX370-Gaming 5
dmi.product.version: Default string
dmi.sys.vendor: Gigabyte Technology Co., Ltd.

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

This change was made by a bot.

[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 v4.16 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/v4.16-rc7

[Knickers Brown (metta-crawler)]

The system in question here used to panic in numerous ways until I started using iommu=pt
Now it appears to be stable.
The BIOS setting for IOMMU is "auto".

[Kai-Heng Feng (kaihengfeng)]

Can you try v4.17 mainline? I guess the issue is solved in mainline.

[Knickers Brown (metta-crawler)]

Please see comment #4

[Kai-Heng Feng (kaihengfeng)]

Comment #4 didn't say which kernel version is in use.

[Knickers Brown (metta-crawler)]

I'm using the default that comes with 18.04
uname -svr
Linux 4.15.0-15-generic #16-Ubuntu SMP Wed Apr 4 13:58:14 UTC 2018

The same IOMMU=pt

$ grep iommu /etc/default/grub
GRUB_CMDLINE_LINUX="iommu=pt"

Fixed 4.14.* on 17.10 (I didn't try the default 4.13.* kernel)
Last tested on 4.14.33-041433-generic (I don't boot 17.10 that often)

[Launchpad Janitor (janitor)]

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[Launchpad Janitor (janitor)]

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