Greeter fails to start after upgrade, session is 'gdm-shell'

[David Beswick]

$ lsb_release -rd
Description: Ubuntu 17.10
Release: 17.10

$ apt-cache policy gdm3
gdm3:
  Installed: 3.26.1-3ubuntu3

I've had this problem on two different machines on which I ran upgrades to Artful.

The greeter never appears after the system boots. It's possible to log in to a different tty, though. When using another tty and running "systemctl restart gdm3", the screen flashes a few times but then returns to the tty.

After enabling GDM debugging by modifying "/etc/gdm3/custom.conf" the journal seems to show that gdm is trying to start a "gdm-shell" session whose file doesn't exist.

To fix the problem, I tried adding these lines to /etc/gdm3/greeter.dconf-defaults:

[org/gnome/desktop/session]
session-name='gnome-login'

However, this didn't make a difference.

"apt get install --reinstall gdm3" also didn't solve the issue.

On both affected systems, I finally found there was a file at "/etc/dconf/db/gdm.d/00-upstream-settings" containing these lines:

[org/gnome/desktop/session]
session-name='gdm-shell'

Changing the configuration here to gnome-login was the only step that solved the problem of those I tried.

I suspect there was some old configuration left around from one of my many upgrades. I found that the file "/etc/dconf/db/gdm.d/00-upstream-settings" doesn't exist after a fresh install of gdm on artful.

Log from journalctl:

Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): emitting SessionIsActive
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): emitting SessionIsActive
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): fill: *** Getting session 'gdm-shell'
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): fill: *** Getting session 'gdm-shell'
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /var/lib/gdm/.config/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /var/lib/gdm/.config/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): Cannot use session '/var/lib/gdm/.config/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): Cannot use session '/var/lib/gdm/.config/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /etc/xdg/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): Cannot use session '/etc/xdg/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /usr/share/gdm/greeter/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): Cannot use session '/usr/share/gdm/greeter/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /usr/local/share/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): Cannot use session '/usr/local/share/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /usr/share/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /etc/xdg/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): Cannot use session '/etc/xdg/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /usr/share/gdm/greeter/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): Cannot use session '/usr/share/gdm/greeter/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /usr/local/share/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): Cannot use session '/usr/local/share/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): fill: *** Looking if /usr/share/gnome-session/sessions/gdm-shell.session is a valid session file
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: DEBUG(+): Cannot use session '/usr/share/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop /usr/lib/gdm3/gdm-wayland-session[22559]: gnome-session-binary[22563]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: DEBUG(+): Cannot use session '/usr/share/gnome-session/sessions/gdm-shell.session': non-existing or invalid file.
Dec 09 08:25:25 david-desktop gnome-session-binary[22563]: CRITICAL: We failed, but the fail whale is dead. Sorry....
Dec 09 08:25:25 david-desktop gdm-wayland-session[22559]: session exited with status 1

[Daniel van Vugt (vanvugt)]

For comparison, the whole directory /etc/dconf/db/gdm.d/ does not exist in a fresh installation of Ubuntu 18.04.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Reinis Danne (readan2)]

Removing /etc/dconf/db/gdm* and restarting gdm solved the issue. Those files were last changed on 2013.10.28.

I still need to add "nomodeset" to the kernel command line to avoid hang-up, but I guess that is different issue.

[Daniel van Vugt (vanvugt)]

Thank you for reporting this bug to Ubuntu.
Ubuntu 17.10 (artful) reached end-of-life on July 19, 2018.

See this document for currently supported Ubuntu releases:
https://wiki.ubuntu.com/Releases

We appreciate that this bug may be old and you might not be interested in discussing it any more. But if you are then please upgrade to the latest Ubuntu version and re-test. If you then find the bug is still present in the newer Ubuntu version, please add a comment here telling us which new version it is in and change the bug status to Confirmed.