[Solved] Gnome-shell hangs on gray screen at login

[g3rb]

Hello, I'm turning to you because I'm encountering a Bug on Debian 12. I'm responsible for a small fleet of workstations integrated with an Active Directory (configured via REALM), and these users (the issue doesn't seem to occur with local sessions on the machine) sometimes fail to open their session. Gnome only displays a gray screen with the cursor in one corner. It's necessary to restart gdm3 to be able to reconnect (sometimes it takes several attempts to open the session). I'm reaching out to you because after scouring the logs, I don't see any concrete leads.

[ruwolf]

Hello.
I think, that part of journal (of systemd) at the time of the unsuccessful login attempt could help here (in the forum).

[g3rb]

Hi ruwolf, thank you for your response. I tried to find something relevant in the journalctl, but I couldn't find anything. Now I've been able to reproduce the bug several times. It seems there's an issue with GDM3 that is causing something wrong during session startup.

pstree:

Normal session startup

├─gdm3─┬─gdm-session-wor─┬─gdm-x-session─┬─Xorg───10*[{Xorg}]
│ │ │ ├─gnome-session-b─┬─ssh-agent
│ │ │ │ └─3*[{gnome-session-b}]
│ │ │ └─2*[{gdm-x-session}]
│ │ └─2*[{gdm-session-wor}]
│ └─2*[{gdm3}]


##### =============================


Gray_screen bug startup

├─gdm3─┬─gdm-session-wor─┬─gdm-x-session─┬─Xorg───10*[{Xorg}]
│ │ │ ├─dbus-run-sessio─┬─dbus-daemo+
│ │ │ │ └─gnome-sess+
│ │ │ └─2*[{gdm-x-session}]
│ │ └─2*[{gdm-session-wor}]
│ ├─gdm-session-wor─┬─gdm-x-session─┬─Xorg───10*[{Xorg}]
│ │ │ ├─gnome-session-b─┬─ssh-agent
│ │ │ │ └─3*[{gnome-+
│ │ │ └─2*[{gdm-x-session}]
│ │ └─2*[{gdm-session-wor}]
│ └─2*[{gdm3}]

It's like one process doesn't want to quit or something?? I will try to reproduce with gdm3 in debug mode.

The journalctl output is attached to this post.

[g3rb]

I think I found a workaround solution. It seems that gdm3 doesn't like to wait for /etc/xdg/autostart/*.desktop. I just moved my scripts (2 automount tasks) to /etc/gdm3/PreSession/Default. Now I don't have this bug anymore.