Ubuntu 18.04 system freezes when attempting to switch user

[Anders Olav Garlid]

Ubuntu 18.04 freezes and must be manually powered down and rebooted when attempting to "Switch User".

Prerequisites:
- Use Ubuntu 18.04
- You need at least 2 users (e.g. user1 and user2)

Expected behavior:
- While logged in as any user, choose "Switch User" from top power drop down.
- Click "Log in as another user"
- Enter another user's credentials and login

Bug behavior and steps to reproduce:
- Start your computer
- At the graphical login prompt, log in with user1: user1 is able to log in, its desktop is shown
- While logged into the desktop of user1, choose "Switch user"
- Returns to login screen, with prompt to enter user1 password
- Click "Log in as another user"
- RESULT: the screen freezes with no ability to type or move the mouse. It is never possible to login in as either user1 or user2 and the system must be manually powered down and restarted.

NOTE 1: the same happens when user2 was the first to log in after a reboot of the system. "Switch User" ends up with the same freeze issue.

NOTE 2: I've been getting crash reports at login that say "System program problem detected / Do you want to report the problem now?". I am unsure whether or not this is related, but the cat _usr_lib_gnome-session_gnome-session-check-accelerated.121.crash file in /var/crash provides the following information at the top of the report:

ProblemType: Crash
Architecture: amd64
CurrentDesktop: GNOME-Greeter:GNOME
Date: Fri Mar 6 11:28:30 2020
DistroRelease: Ubuntu 18.04
ExecutablePath: /usr/lib/gnome-session/gnome-session-check-accelerated
ExecutableTimestamp: 1525246842
ProcCmdline: /usr/lib/gnome-session/gnome-session-check-accelerated
ProcCwd: /var/lib/gdm3
ProcEnviron:
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/false

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gdm3 3.28.3-0ubuntu18.04.4
ProcVersionSignature: Ubuntu 5.3.0-40.32~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-40-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.11
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Fri Mar 6 11:49:25 2020
InstallationDate: Installed on 2020-03-03 (2 days ago)
InstallationMedia: Ubuntu 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203.1)
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: gdm3
UpgradeStatus: No upgrade log present (probably fresh install)

NOTE 3: I've come to a pseudo-resolution by disabling Wayland usage in gdm3.

 - Edit /etc/gdm3/custom.conf and simply uncomment:
#WaylandEnable=false

 - restart everything and Switch Users works fine.

[Anders Olav Garlid (aogarlid)]

I've come to a pseudo-resolution by disabling Wayland usage in gdm3.

 - Edit /etc/gdm3/custom.conf and simply uncomment:
#WaylandEnable=false

 - restart everything and Switch Users works fine.

I included this comment as "NOTE 3" in the bug report.

[Daniel van Vugt (vanvugt)]

Please:

1. Run:

   lspci -k > lspcik.txt

   and attach the file 'lspcik.txt'

2. Reproduce the issue, then reboot and immediately run:

   journalctl -b-1 > prevboot.txt

   and attach the file 'prevboot.txt' here.

3. Also follow these instructions in case something has crashed:

   https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment