Public bug reported:
Title: GDM login screen has no login box or user list after first reboot
in 47 days; autologin did not run (gnome-shell 50.1: "JS ERROR: Error:
Argument child may not be null")
Summary
After a power outage and the first reboot in about 47 days, the machine came up
to the GDM login screen (gdm-greeter session on seat0/tty1) showing the top
bar, clock, calendar popup and system menu, but no login dialog and no user
list. The system menu only offered Suspend, Restart and Power Off. Autologin,
which is how this machine normally boots, did not happen. SSH and background
services worked normally.
Environment
Ubuntu 26.04.1 LTS, kernel 7.0.0-38-generic, Wayland, AMD GPU (amdgpu),
full-disk LUKS encryption.
At first failure (boot of Oct 11 12:47): gnome-shell 50.1-0ubuntu1.2, mutter
50.1-0ubuntu2.2, gdm3 50.1-0ubuntu0.1. The problem persisted after upgrading to
gnome-shell 50.1-0ubuntu1.3 and mutter 50.1-0ubuntu2.4.
Update history
The machine ran from Aug 23 to Oct 9 without a reboot, with unattended upgrades
installed in that period (kernel 7.0.0-30 to -38, mesa 26.0.3 to 26.0.8, glib
2.88.0-1 to 1ubuntu0.1, librsvg2 on Oct 7, gnome-shell-common 50.1-0ubuntu1 to
1.2). Oct 11 was the first reboot since, so I can't tell whether the outage or
one of these updates is the trigger.
Expected
Either the autologin session starts, or the greeter shows a user list or login
prompt.
Actual
The greeter's journal shows at startup:
gnome-shell: Could not load a pixbuf from
/org/gnome/shell/icons/scalable/actions/accessibility-high-contrast-symbolic.svg
gnome-shell: JS ERROR: Error: Argument child may not be null
The JS ERROR repeats later in the same greeter session. The pixbuf warning also
appears in a working user session, so it is probably unrelated.
The journals for the first two boots after the outage contain no gdm-autologin
or gdm-password entries.
Workaround and what it shows
Setting AutomaticLoginEnable=true and AutomaticLogin=<user> in
/etc/gdm3/custom.conf and restarting gdm3 gives a normal "ubuntu" session with
no JS errors (tested with a brand-new user and with my normal user).
User sessions work; only the greeter is broken.
What I already tried (no change to the greeter)
- Reinstalled gdm3, gnome-shell, gnome-shell-common, mutter, mesa,
xserver-xorg, librsvg2-common, libgdk-pixbuf-2.0-0
- update-mime-database, glib-compile-schemas, dpkg-reconfigure gdm3
- Removed /var/lib/gdm3/.config, .local and .cache contents
- debsums -c reports no modified files; no zero-length files; ext4 showed
only a normal orphan cleanup after the outage
- /var/lib/gdm3/greeter-dconf-defaults exists, is the same size as the shipped
/usr/share/gdm/greeter-dconf-defaults, and is regenerated when GDM starts
Not known
- What /etc/gdm3/custom.conf contained at the time of failure; I edited it
while troubleshooting.
- Why autologin did not run after the outage.
ProblemType: Bug
DistroRelease: Ubuntu 26.04
Package: gnome-shell 50.1-0ubuntu1.3
ProcVersionSignature: Ubuntu 7.0.0-38.38-generic 7.0.14
Uname: Linux 7.0.0-38-generic x86_64
ApportVersion: 2.34.1-0ubuntu0.1
Architecture: amd64
CasperMD5CheckResult: pass
Date: Sun Oct 11 23:48:21 2026
DisplayManager: gdm3
GsettingsChanges:
b'org.gnome.shell' b'welcome-dialog-last-shown-version' b"'50.1'"
b'org.gnome.desktop.app-folders' b'folder-children' b"['System', 'Utilities',
'YaST', 'Pardus']"
b'org.gnome.desktop.input-sources' b'sources' b"[('xkb', 'us')]"
b'org.gnome.mutter.keybindings' b'toggle-tiled-left' b'@as []'
b'org.gnome.mutter.keybindings' b'toggle-tiled-right' b'@as []'
InstallationDate: Installed on 2026-05-07 (158 days ago)
InstallationMedia: Ubuntu 26.04 "Resolute Raccoon" - Release amd64 (20260423.1)
ProcEnviron:
LANG=en_US.UTF-8
PATH=(custom, no user)
SHELL=/bin/bash
TERM=xterm-256color
XDG_RUNTIME_DIR=<set>
RelatedPackageVersions: mutter-common 50.1-0ubuntu2.4
SourcePackage: gnome-shell
UpgradeStatus: No upgrade log present (probably fresh install)
** Affects: gnome-shell (Ubuntu)
Importance: Undecided
Status: New
** Tags: amd64 apport-bug resolute
** Attachment added: "greeter’s journal from the first failing boot"
https://bugs.launchpad.net/bugs/2170518/+attachment/6008367/+files/greeter.log
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https://bugs.launchpad.net/bugs/2170518
Title:
Login window doesn't render, shows black desktop.
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