Choosing "Try Ubuntu" on daily-legacy image produced a crash

[Brian Murray]

I was booting up a daily-legacy image from 20230918 and received a crash report after choosing "Try Ubuntu".

ProblemType: Crash
DistroRelease: Ubuntu 23.10
Package: gnome-shell 45~rc-0ubuntu3
Uname: Linux 6.5.0-5-generic x86_64
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Mon Sep 18 15:20:58 2023
ExecutablePath: /usr/bin/gnome-shell
ExecutableTimestamp: 1694375959
ProcCmdline: gnome-shell --sm-disable --mode=ubiquity
ProcCwd: /home/ubuntu
ProcEnviron:
 LANG=C.UTF-8
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
Signal: 6
SourcePackage: gnome-shell
UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo users

[Apport retracing service (apport)]

Thank you for your report!

However, processing it in order to get sufficient information for the
developers failed as the report has a core dump which is invalid. The
corruption may have happened on the system which the crash occurred or during
transit.

Thank you for your understanding, and sorry for the inconvenience!

[Brian Murray (brian-murray)]

Looking at the retracer log file regarding this crash something seems amiss.

09/18/23 15:39:06: fill_pool: retrace pool now: {2036440}
09/18/23 15:39:06: retracing LP: #2036440 (left in pool: 0)
09/18/23 15:39:13: retracing LP: #2036440 failed with status: 1
ERROR: Invalid core dump: "/tmp/apport_core_8b0m3n31" is not a core dump: file format not recognized

I'd have expected the core dump to part of the crash file.

[Brian Murray (brian-murray)]

I'm attaching the crash file which does have a CoreDump section.

[Brian Murray (brian-murray)]

This bears some investigation into whether or not the core dump is actually a part of the crash file and if not why it isn't. We want to be able to provide crash reports from the live environment.

[Brian Murray (brian-murray)]

I'm manually able to retrace the crash file from comment #4, although that fails, with the apport. Perhaps there is a period of time where the core dump is not attached to the crash file?

[Benjamin Drung (bdrung)]

Since this crash is about gnome-shell, maybe this is just another case of bug #2015857?

[Daniel van Vugt (vanvugt)]

Signal 6 is SIGABRT which usually means an assertion failed, which means the system log will contain an explanation. Next time it happens please run:

  journalctl -b0 > journal.txt

and attach the resulting text file here.

[Brian Murray (brian-murray)]

Couldn't we modify the apport hook for gnome-shell to gather the relevant log file when ever there is a 'Signal: 6' in the crash report?

[Daniel van Vugt (vanvugt)]

Indeed I've been meaning to learn about apport because I would like ALL bug reports to automatically come with:

  journalctl -b0 > journal.txt
  journalctl -b-1 > prevjournal.txt

[Brian Murray (brian-murray)]

gnome-shell already ships an apport package hook which is installed in /usr/share/apport/package-hooks/source_gnome-shell.py and that seems to be debian/source_gnome-shell.py from the source package. It should be relatively straight forward to modify that and an update to it is something the SRU team would likely (I say likely due to the install base of gnome-shell) as an stable release update to the package. It is something the Ubuntu Release team would definitely accept as an update post Feature Freeze.

[Daniel van Vugt (vanvugt)]

I meant all bug reports, not just gnome-shell. But gnome-shell is the best place to start.

[Brian Murray (brian-murray)]

Oh, in that case you'll want to look at /usr/share/apport/general-hooks/ubuntu.py which is provided by the apport package.

[Daniel van Vugt (vanvugt)]

I have more questions than answers now...

* It looks like source_gnome-shell.py already attaches journalctl output, so why didn't it here?

* data/general-hooks/generic.py also attaches journal errors, so why didn't it here?

* Do we really want all Ubuntu bug reports to have journal data that might be sensitive?

* Can we compress system logs before attaching them?

* Why is ubuntu.py source maintained in debian/patches/Add-general-hooks.patch instead of a standalone file?

* What's the criteria for going in ubuntu.py vs upstream https://github.com/canonical/apport ?

It all seems a little too hard right now. I have other things I need to be doing instead of learning apport and Python.

[Brian Murray (brian-murray)]

The gnome-shell crash is easily reproducible by choosing Try Ubuntu when using a mantic desktop legacy image.

[Daniel van Vugt (vanvugt)]

Unfortunately that log doesn't contain a gnome-shell crash.

[Brian Murray (brian-murray)]

We could create an /etc/apport/report-ignore/ file with the contents '/usr/bin/gnome-shell' so then at least the crash report dialog would not appear. However, after choosing try Ubuntu you presented with a black screen and some console output so its still not a great experience.

[Brian Murray (brian-murray)]

Could the gnome-shell crash be a consequence of how we are booting the Legacy image and starting the desktop environment? I noticed the following in the crash report "gnome-shell --sm-disable --mode=ubiquity".