Gnome Shell does not start in Xorg mode

[Owais Lone]

In Ubuntu 17.10 and 17.04, Gnome session has stopped working with the X11 mode for me. Selecting "Ubuntu on X" in GDM logs me in to a black screen with the cursor. If I have an app configured to auto start, the app launches without any window decorations. Clicking the app through File > Quit menu turns the cursor in a black cross.
---
ApportVersion: 2.20.8-0ubuntu5
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
DisplayManager: gdm3
DistroRelease: Ubuntu 18.04
InstallationDate: Installed on 2017-11-19 (30 days ago)
InstallationMedia: Ubuntu 17.10 "Artful Aardvark" - Release amd64 (20171018)
Package: gnome-shell 3.26.2-0ubuntu2
PackageArchitecture: amd64
ProcVersionSignature: Ubuntu 4.13.0-17.20-generic 4.13.8
Tags: third-party-packages wayland-session bionic
Uname: Linux 4.13.0-17-generic x86_64
UpgradeStatus: Upgraded to bionic on 2017-12-01 (18 days ago)
UserGroups: adm cdrom dip docker lpadmin plugdev sambashare sudo
_MarkForUpload: True

[Owais Lone (loneowais)]

Possibly related issue: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1739022

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please execute the following command only once, as it will automatically gather debugging information, in a terminal:

apport-collect 1739019

When reporting bugs in the future please use apport by using 'ubuntu-bug' and the name of the package affected. You can learn more about this functionality at https://wiki.ubuntu.com/ReportingBugs.

[Owais Lone (loneowais)]

apport information

[Owais Lone (loneowais)]

apport information

[Owais Lone (loneowais)]

apport information

[Owais Lone (loneowais)]

apport information

[Owais Lone (loneowais)]

apport information

[Owais Lone (loneowais)]

I've uploaded the report but from a working Wayland session as Xorg does not run at all.

[Daniel van Vugt (vanvugt)]

Thanks. This log message of yours might be related:

Dec 20 07:39:17 hostname gnome-shell[1471]: setup_framebuffers: assertion 'width > 0' failed
Dec 20 07:39:17 hostname gnome-shell[1471]: setup_framebuffers: assertion 'width > 0' failed

Please try removing your monitor config file (delete or rename): ~/.config/monitors.xml
and then log in again.

If that doesn't work, please also attach:
 * Output from 'lspci -k'
 * /var/log/Xorg.* (from immediately after the problem has been reproduced)

[Owais Lone (loneowais)]

It didn't work unfortunately. Attaching the files.

[Owais Lone (loneowais)]

I had removed old Xorg.log files from /var/log last time I was trying to debug this. Strangely, the files are not even generated now anymore even if I try to login to Xorg session

[Owais Lone (loneowais)]

I had removed old Xorg.log files from /var/log last time I was trying to debug this. Strangely, the files are not even generated now anymore even if I try to login to Xorg session.

A video demonstrating the problem: https://photos.app.goo.gl/TD9TgNGC9zjeENGP2

[Owais Lone (loneowais)]

Can I provide any more information or try something else to fix?

[Daniel van Vugt (vanvugt)]

OK. Keep an eye out for new Xorg.log files.

In the mean time, please try:

1. From the login screen go Ctrl+Alt+F4 and log into the text console.
2. Ctrl+Alt+F1 to return to the login screen.
3. Try to log into Xorg mode again.
4. While the Xorg session is failing to start, return to Ctrl+Alt+F4 and run:
    journalctl > latestlog.txt
5. Attach latestlog.txt here.

[Owais Lone (loneowais)]

The failure at end represents a failed login attempt after I switched to terminal using cmd+alt+F4

[Daniel van Vugt (vanvugt)]

Thanks. It looks like Xorg is running but sounds like gnome-shell is missing or hung.

Do you find any crash files in /var/crash? If so, please use the 'ubuntu-bug' command to upload them and also add a comment here mentioning the new bug ID.

Otherwise...

While your screen is black, switch VTs again (Ctrl+Alt+F4 or really anything from F3 upward) and login. Now does 'ps auxw | grep gnome-shell' show any gnome-shell process? If so then please force it to dump a crash file with something like this:

  kill -TRAP <pid-of-gnome-shell>

And look in /var/crash again, per above.

[Launchpad Janitor (janitor)]

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