Boot hangs before graphic login

[Anders Kühne]

Please note: there are obviously several different causes for this error. Other reports on launchpad and elsewhere identified sddm, systemd, nvidia drivers and grub config. Since none of the solutions mentioned there helped in my case, I am deliberately leaving the information on the source package open.

I have upgraded to Kubuntu Vivid 15.04 shortly after the final release and used that without issues until two days ago when I ran updates (apt log attached).

Ran »sudo systemctl enable sddm.service -f«, then reboot: no change.

Changed the GRUB_CMDLINE_LINUX_DEFAULT option in /etc/default/grub to include »nomodeset«: no change. Other variations of this line did not help, either.

I do not have nvidia or nouveau driver packages installed.

I am aware that 219 is the current systemd version, so I tried the upstart option in grub. Hangs, too (though with different error message).

»systemctl start sddm« asks for password, the returns »authentication complete« (in all-caps); nothing else happens.

Re-installing linux-generic or kubuntu-desktop had no effect.

What can I do to at least identify the cause of this issue?

[Martin Pitt (pitti)]

Can you please boot with dropping "quiet" and "splash", by editing the "linux" line in the GRUB boot menu. Where do you end up? Do you get a "login:" prompt where you can login? If not, please do a screenshot (with a camera) and attach that, there's hopefully some text which shows where exactly it gets stuck. Where did you type the "systemctl start sddm" command? is that a rescue shell, or did you log in as your user?

Either way, if you are able to run commands, please try to attach /var/log/syslog to this bug, it should have some useful information. Thanks!

[Anders Kühne (andreas-kuhne)]

Removing "quiet" and "splash" results in the kubuntu logo and the "starting version 219" message not showing up, boot messages instead but just a black screen in the end. I could not make much of the syslog, see attached. There are no errors in Xorg.0.log, BTW.

I ran the "systemctl start sddm" from tty2, logged in as my user. Just retried from a rescue shell: "Error getting authority: Error initializing authority: [...] (g-io-error-quark, 1)". /etc/X11/default-display-manager has "/usr/bin/sddm".

[Anders Kühne (andreas-kuhne)]

One Thing I can add is the last lines in boot.log:

[OK] Started /etc/rc.local Compatibility.
        Starting Wait for Plymouth Boot Screen to Quit...
        Starting Terminate Plymouth Boot Screen...

[Anders Kühne (andreas-kuhne)]

Found that apt-get kept some packages on hold, resolved dependencies with aptitude, to no avail. Did a clean re-install in the meantime. I still see the "starting version 219" message but then the login screen appears and everything works.

[Martin Pitt (pitti)]

Indeed the log looks just fine -- it starts sddm and the user session. As you now reinstalled, any further evidence is lost I'm afraid, so I'll just duplicate this.