[chiark.chat] Re: RFH: sysvinit etc. in Debian

[Peter Maydell]

In article <5bzhvedpsy.fsf at chiark.greenend.org.uk> you write:
>{some stuff from me initially}
>Issues noted:
>  * gdm doesn't work at all -- it puts "Unable to register display with
>display manager"  in the greeter log and there's syslog entries
>"gdm3: Child process -2650 was already dead". The auth.log says it is
>successfully creating a login session, but something's presumably going
>wrong after that...

I found out how to turn on gdm debug (in /etc/gdm3/daemon.conf),
and now get a lot more logging in /var/log/user.log. Notably
suspicious:

Oct 17 20:06:20 buster gdm-launch-environment]: GdmSessionWorker: state SESSION_STARTED
Oct 17 20:06:20 buster gdm-launch-environment]: GdmSession worker: watching pid 2425
Oct 17 20:06:20 buster gdm3: GdmSession: Emitting 'session-started' signal with pid '2425'
Oct 17 20:06:20 buster gdm3: GdmDisplay: Greeter started
Oct 17 20:06:20 buster gdm-launch-environment]: GdmSessionWorker: could not take control of tty: Operation not permitted
Oct 17 20:06:20 buster gdm-wayland-session: Enabling debugging
Oct 17 20:06:20 buster gdm-wayland-session: Running session message bus
Oct 17 20:06:20 buster gdm-wayland-session: GLib: posix_spawn avoided (fd close requested) (child_setup specified) 
Oct 17 20:06:20 buster gdm-wayland-session: could not fetch environment: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name org.freedesktop.systemd1 was not provided by any .service files
Oct 17 20:06:20 buster gdm-wayland-session: Running wayland session
Oct 17 20:06:20 buster gdm-wayland-session: GLib: posix_spawn avoided (fd close requested) (child_setup specified) 
Oct 17 20:06:20 buster gdm3: GdmManager: trying to register new display
Oct 17 20:06:20 buster gdm3: GdmManager: Error while retrieving session id for sender: Error getting session id from systemd: No such file or directory
Oct 17 20:06:20 buster gdm-wayland-session: Could not register display: GDBus.Error:org.freedesktop.DBus.Error.AccessDenied: No display available
Oct 17 20:06:20 buster gdm-launch-environment]: GdmSessionWorker: child (pid:2425) done (status:70)
Oct 17 20:06:20 buster gdm-launch-environment]: GdmSessionWorker: uninitializing PAM
Oct 17 20:06:20 buster gdm-launch-environment]: GdmSessionWorker: state NONE
Oct 17 20:06:20 buster gdm3: GdmSession: Emitting 'session-exited' signal with exit code '70'

I think the gdm-wayland-session complaint about not finding
org.freedesktop.systemd1 means it wants specifically to talk
to systemd, not just logind, for some reason (the function
is for getting an environment). The "Error getting session id from
systemd" is because sd_pid_get_session() in libsystemd failed.

Maybe gdm is just too tied to systemd to be worth trying to
debug at this point?

thanks
-- PMM