User switch not possible, login screen black

[Johon Doee]

The bug presents itself the following way:

It occurs with update to gdm3 3.24.1-0ubuntu0.1. Did not happen before, downgrade to gdm3 3.24.0-0ubuntu2 solves the problem.

My session does auto-start. After the desktop is loaded I try to switch to another user. The screen goes black for some seconds and switches back to the primary user. No login screen or user chooser is visible. After trying that one time, also logout is not possible anymore. After logout I do not see the login greeter but a black screen instead.

Ubuntu Gome 17.04
Skylake 520

ProblemType: Bug
DistroRelease: Ubuntu 17.04
Package: gdm3 3.24.1-0ubuntu0.1
ProcVersionSignature: Ubuntu 4.10.0-21.23-generic 4.10.11
Uname: Linux 4.10.0-21-generic x86_64
ApportVersion: 2.20.4-0ubuntu4
Architecture: amd64
CurrentDesktop: GNOME
Date: Wed May 17 08:28:01 2017
InstallationDate: Installed on 2016-04-21 (390 days ago)
InstallationMedia: Ubuntu-GNOME 16.04 LTS "Xenial Xerus" - Release amd64 (20160421)
SourcePackage: gdm3
UpgradeStatus: Upgraded to zesty on 2017-04-13 (33 days ago)
mtime.conffile..etc.gdm3.custom.conf: 2017-05-17T08:12:46.076209

[Johon Doee (jodoee11)]

Also to add: It does not matter if the custom.conf file is standard or with the modification I made (which is not really a modification anyways).

[Jeremy Bícha (jbicha)]

I am setting the importance to Critical since this is a regression introduced in a Ubuntu Stable Release Update according to #7 of https://wiki.ubuntu.com/StableReleaseUpdates#Procedure

[Jeremy Bícha (jbicha)]

Johon, the system journal excerpt attached to this bug has this line:
Mai 17 08:27:51 username-201604 gdm-autologin][3152]: gkr-pam: no password is available for user

And your GDM configuration has these lines:
AutomaticLoginEnable = true
AutomaticLogin = ubuntu

Is your username 'ubuntu'?
Does your user have a password?

[Johon Doee (jodoee11)]

Jeremy, thank you for looking into this regression.

To answer your questions: Yes, my username is ubuntu, yes I do have a password for that user.

[Jeremy Bícha (jbicha)]

Hmm, I enabled auto login and restarted after applying this update and I still couldn't reproduce the issue. (I was able to log out and log back in and switch to a different user).

What graphics driver are you using?

[Johon Doee (jodoee11)]

Hm, strange.

I use the standard intel graphics drivers that come with ubuntu. I did not install anything else.

Maybe it's a problem of the users I have created?

I created 3 other users (see below with their respective UID).

ubuntu:1000
user1:1001
user2:999
user3:1002

Only ubuntu and user3 have passwords set. user1 and user2 do not appear in the login screen (I removed both from login screen).

Anyways - could that be the problem? But if so - why did this does not make problems with the former gdm3-version?

[Johon Doee (jodoee11)]

Any progress on that matter?

[Launchpad Janitor (janitor)]

[Expired for gdm3 (Ubuntu) because there has been no activity for 60 days.]

[Launchpad Janitor (janitor)]

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

[Fred Vkigg (fvkigg)]

I see this same behaviour on 2 machines with 18.04 when I have no swap. With swap enable the problem goes away. Bug did not exist in 17.10 or I believe until quite late in the 18.04 development cycle.