GDM/gnome-shell crash/freeze when switching keyboard layouts

[hn23]

on my pc there are multiple keyboard layouts configured.(EN/JA/DE)
When using the keyboard shortcut to switch the layout (Super+Space) in some situations (criteria not entirely clear) the whole UI freezes up and becomes unresponsive. The only workaround is a hard poweroff and reboot of the system which is rather convenient if this happens multiple times during a work day.

When switching to another terminal (Alt+F2 etc) I cam see `/usr/lib/gdm3/gdm-x-session` having a high CPU load.

In the attached syslog file, there are repeated entries about

1) all input devices being removed
2) systemd-logind being paused

```
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "21"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event2 - Power Button: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "24"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event4 - Video Bus: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "25"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event1 - Sleep Button: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "26"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event5 - Microsoft Microsoft® Nano Transceiver v2.1: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "27"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event6 - Microsoft Microsoft® Nano Transceiver v2.1 Mouse: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "28"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "29"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "30"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event9 - Microsoft Microsoft® Nano Transceiver v2.1 System Control: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "31"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event3 - AT Translated Set 2 keyboard: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "32"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event10 - SynPS/2 Synaptics TouchPad: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "33"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event11 - TPPS/2 IBM TrackPoint: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "34"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event12 - ThinkPad Extra Buttons: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "28"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event7 - Microsoft Microsoft® Nano Transceiver v2.1 Consumer Control: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (**) Option "fd" "29"
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) event8 - Microsoft Microsoft® Nano Transceiver v2.1 Consumer Control: device removed
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) AIGLX: Suspending AIGLX clients for VT switch
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) systemd-logind: got pause for 13:74
Mar 31 22:40:25 mangan /usr/lib/gdm3/gdm-x-session[1811]: (II) systemd-logind: got pause for 13:71

``

ProblemType: Bug
DistroRelease: Ubuntu 18.04
Package: gnome-shell 3.28.4-0ubuntu18.04.3
ProcVersionSignature: Ubuntu 5.3.0-45.37~18.04.1-generic 5.3.18
Uname: Linux 5.3.0-45-generic x86_64
ApportVersion: 2.20.9-0ubuntu7.13
Architecture: amd64
CurrentDesktop: ubuntu:GNOME
Date: Thu Apr 2 00:03:10 2020
DisplayManager: gdm3
InstallationDate: Installed on 2020-03-13 (19 days ago)
InstallationMedia: Ubuntu 18.04.4 LTS "Bionic Beaver" - Release amd64 (20200203.1)
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)

[Daniel van Vugt (vanvugt)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. It sounds like some part of the system has crashed. To help us find the cause of the crash please follow these steps:

1. Look in /var/crash for crash files and if found run:
    ubuntu-bug YOURFILE.crash
Then tell us the ID of the newly-created bug.

2. If step 1 failed then look at https://errors.ubuntu.com/user/ID where ID is the content of file /var/lib/whoopsie/whoopsie-id on the machine. Do you find any links to recent problems on that page? If so then please send the links to us.

3. If step 2 also failed then apply the workaround from bug 994921, reboot, reproduce the crash, and retry step 1.

Please take care to avoid attaching .crash files to bugs as we are unable to process them as file attachments. It would also be a security risk for yourself.

[Launchpad Janitor (janitor)]

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