OK, I have finished the bisect.

3f6a3b035f91a22c0d3bd27630bf61eac9c8cf6c is the first bad commit. I
tested it and it displays the problem, and I tested
abd39ac1da07b433fc570332ee9ad938b5071760 right before it and that one
boots fine.

On Sat, Jul 21, 2018 at 9:42 AM, Adam Novak <email address hidden> wrote:
> That one works. On to 5856293c78e552c012835e667d66775bba20b4f7.
>
> I suspect 3f6a3b035f91 and abd39ac1da07 may be the real problem, since
> the CPU I am using is an AMD Ryzen chip, and those are tinkering
> specifically with how the kernel handles those.
>
> On Fri, Jul 20, 2018 at 10:23 PM, Adam Novak <email address hidden> wrote:
>> OK, I tried that one and it still exhibited the issue. I'm going to
>> try 91762b4035d9da8c266e2cb3dbc552052434bbf0 next.
>>
>> On Fri, Jul 20, 2018 at 9:08 PM, Adam Novak <email address hidden> wrote:
>>> Thanks!
>>>
>>> I have tested this kernel; it doesn't work, so the problem is between
>>> fc8704280f2ada9f61f08a2d5adc0dab169cc207 and
>>> 8eca6add0defde203282476d7969a7c13bbd7d91.
>>>
>>> I've gotten set up with a kernel build environment; I think I can
>>> finish the git bisect myself, but looking at the commits in that
>>> range, I have no hope of actually fixing the underlying bug myself.
>>> I'm building 3f6a3b035f91a22c0d3bd27630bf61eac9c8cf6c now.
>>>
>>> On Tue, Jul 17, 2018 at 11:24 AM, Joseph Salisbury
>>> <email address hidden> wrote:
>>>> I built the next test kernel, up to the following commit:
>>>> fc8704280f2ada9f61f08a2d5adc0dab169cc207
>>>>
>>>> The test kernel can be downloaded from:
>>>> http://kernel.ubuntu.com/~jsalisbury/lp1777338
>>>>
>>>> Can you test that kernel and report back if it has the bug or not? I
>>>> will build the next test kernel based on your test results.
>>>>
>>>> Thanks in advance
>>>>
>>>>
>>>> MD5SUM of files:
>>>> d76993d34e1203375090a47c4de8ebfe  linux-image-unsigned-4.15.0-23-generic_4.15.0-23.26~lp1777338Commitfc8704280f_amd64.deb
>>>>
>>>> 5b89b2341b858bbe2bcae88e3efaf8c8  linux-
>>>> modules-4.15.0-23-generic_4.15.0-23.26~lp1777338Commitfc8704280f_amd64.deb
>>>>
>>>> 6928b4ad5f2a861ad674ff88a4745471  linux-modules-
>>>> extra-4.15.0-23-generic_4.15.0-23.26~lp1777338Commitfc8704280f_amd64.deb
>>>>
>>>> --
>>>> You received this bug notification because you are subscribed to the bug
>>>> report.
>>>> https://bugs.launchpad.net/bugs/1777338
>>>>
>>>> Title:
>>>>   Linux 4.15.0-23 crashes during the boot process with a "Unable to
>>>>   handle kernel NULL pointer dereference" message
>>>>
>>>> Status in linux package in Ubuntu:
>>>>   In Progress
>>>> Status in linux source package in Bionic:
>>>>   In Progress
>>>>
>>>> Bug description:
>>>>   I went to boot my computer today and it wouldn't boot.
>>>>
>>>>   I get an "Unable to handle kernel NULL pointer dereference" message
>>>>   during the boot process, and, a bit after that, a message from the
>>>>   kernel watchdog about CPU #0 being stuck. Then the boot process stops
>>>>   completely.
>>>>
>>>>   I was able to boot the system by telling Grub to load 4.15.0-22, which
>>>>   works perfectly fine, so there has been a regression.
>>>>
>>>>   I am running Ubuntu as a Xen dom0, if that matters. I haven't tried
>>>>   booting the offending kernel version without Xen.
>>>>
>>>>   I'm not sure where, if anywhere, these messages go on disk, for
>>>>   posting.
>>>>
>>>>   ProblemType: Bug
>>>>   DistroRelease: Ubuntu 18.04
>>>>   Package: linux-image-4.15.0-23-generic 4.15.0-23.25
>>>>   ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17
>>>>   Uname: Linux 4.15.0-22-generic x86_64
>>>>   NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
>>>>   ApportVersion: 2.20.9-0ubuntu7.1
>>>>   Architecture: amd64
>>>>   CurrentDesktop: ubuntu:GNOME
>>>>   Date: Sun Jun 17 10:12:58 2018
>>>>   InstallationDate: Installed on 2017-08-06 (314 days ago)
>>>>   InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412)
>>>>   ProcEnviron:
>>>>    TERM=xterm-256color
>>>>    PATH=(custom, no user)
>>>>    XDG_RUNTIME_DIR=<set>
>>>>    LANG=en_US.UTF-8
>>>>    SHELL=/bin/bash
>>>>   SourcePackage: linux-signed
>>>>   UpgradeStatus: Upgraded to bionic on 2018-05-29 (19 days ago)
>>>>
>>>> To manage notifications about this bug go to:
>>>> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1777338/+subscriptions