No login screen when fprintd crashes

[Vincent Gerris]

After a recent update, when using gdm3 as login manager, there is no account visible and it is not possible to login.
When switching to lightdm I can login but sleep is broken and some notifications do not work.
Running the latest 22.04 dev branch with Wayland and Nvidia driver.
Had to select kernel 5.12 to have display link working.
This issue occurs with and without external displays attached.
A recent attempt to switch back to gdm3 gave me just a black screen.

I tried to reinstall gdm3 to no avail.
This seems like a quite serious issue, hence this report for the dev version.
---
ProblemType: Bug
ApportVersion: 2.20.11-0ubuntu76
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: ubuntu:GNOME
DisplayManager: lightdm
DistroRelease: Ubuntu 22.04
InstallationDate: Installed on 2019-12-17 (784 days ago)
InstallationMedia: Ubuntu 19.10 "Eoan Ermine" - Release amd64 (20191017)
NonfreeKernelModules: nvidia_modeset wl nvidia
Package: gnome-shell 41.3-1ubuntu1
PackageArchitecture: amd64
RelatedPackageVersions: mutter-common 41.3-1ubuntu1
Tags: third-party-packages jammy
Uname: Linux 5.12.19-051219-generic x86_64
UpgradeStatus: No upgrade log present (probably fresh install)
UserGroups: adm cdrom dialout dip docker libvirt lpadmin lxd microk8s plugdev sambashare sudo
_MarkForUpload: True

[Daniel van Vugt (vanvugt)]

The login screen is provided by 'gnome-shell' so reassigning there.

Also please run these commands to gather more information from the machine:

  apport-collect 1960336
  lspci -k > lspci.txt
  journalctl -b-1 > prevboot.txt

and attach the resulting text files here.

In future please be sure to report bugs using the 'ubuntu-bug' command which will collect the required information automatically.

[Daniel van Vugt (vanvugt)]

To avoid confusion we should also not mention DisplayLink here. That's a separate issue so if you have problems with DisplayLink then please open a new bug about that.

[Vincent Gerris (vgerris)]

apport information

[Vincent Gerris (vgerris)]

apport information

[Vincent Gerris (vgerris)]

apport information

[Vincent Gerris (vgerris)]

apport information

[Vincent Gerris (vgerris)]

apport information

[Vincent Gerris (vgerris)]

apport information

[Vincent Gerris (vgerris)]

ran apport and added files, thank you.

[Vincent Gerris (vgerris)]

lspci output

[Marc Doughty (mangeek)]

Not sure if it's the same issue, but a fresh load of the preinstalled Jammy image on Raspberry Pi 4 goes through most of initial setup, but then goes to a blank screen. Subsequent reboots and restarts of gdm3 lead to a console screen with a blinking cursor instead of the login screen. Manually starting a GNOME session from the console works.

[Daniel van Vugt (vanvugt)]

Comment #11 is probably bug 1960226, not 1960336 :)

[Daniel van Vugt (vanvugt)]

Vincent,

Thanks for the quick response. Please try uninstalling your shell extensions:

  '<email address hidden>', '<email address hidden>'

and then reboot. If the problem persists (with gdm3) then please take a photo of the screen and attach it here.

gdm3 is a little suspicious at the moment because it might be the cause of bug 1960226 too. Not sure.

[Daniel van Vugt (vanvugt)]

Please also try this update, it sounds promising:

https://launchpad.net/ubuntu/+source/gdm3/41.3-1ubuntu2

[Daniel van Vugt (vanvugt)]

Since Dependencies.txt shows you have the broken (41.3-1ubuntu1) gdm3 installed, we can probably assume this really is bug 1960226. Although it's the first case of someone hitting it via updates that I have heard of. Previously it seemed like you would only have a problem if you installed from this week's ISOs.

Please test gdm3 version 41.3-1ubuntu2

[Vincent Gerris (vgerris)]

Hi Daniel,

Where can I find these extensions?
They are not in apt search, .local/share/gnome-shell/extensions or in extensions app.

I did an apt get update and installed the new gdm3 version you mention.
Then sudo dpkg-reconfigure gdm3 and now it actually showed me the choice between lightdm and gdm3 ( did not do that on previous version).

Unfortunately, the result is the same.
I get a black screen. If I try other ttys, some show a flashing cursor, but I can´t do anything.
The off button responds so the system is not hanging.

Also did a reinstall of gnome-shell package, no success.
So a photo would just be a black screen :).

[Daniel van Vugt (vanvugt)]

Please double check that the installed gdm3 version is 41.3-1ubuntu2 and not 41.3-1ubuntu1.

You can disable extensions in the 'Extensions' app. If that's not already installed then:

  sudo apt install gnome-shell-extension-prefs

[Vincent Gerris (vgerris)]

hi, I did :
ubuntu@ubuntu-inspiron-5482:~$ dpkg -l gdm3
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-==============-=============-============-=================================
ii gdm3 41.3-1ubuntu2 amd64 GNOME Display Manager

The extensions do not show up in the extensions app, I cannot find a trace anywhere.
A screenshot is attached from the app ( that in fact does not seem to follow the theme :) ).

Also no extensions show on extensions.gnome.org/local.
Thank you again for the quick reply!

[Daniel van Vugt (vanvugt)]

In the Extensions app please toggle the switch that is next to 'Caffeine' off. Then log in again.

[Vincent Gerris (vgerris)]

hi, I tried, same problem.

[Daniel van Vugt (vanvugt)]

I think most likely the problem is a side effect of the customizations this machine has experienced over the years. Like switching display managers multiple times, or using a non-standard kernel.

I would suggest the fastest way to a fix might be to just reinstall fresh: http://cdimage.ubuntu.com/daily-live/current/

If you need DisplayLink support for kernel 5.13 then I can confirm the 5.5 beta driver works well: https://www.synaptics.com/products/displaylink-graphics/downloads/ubuntu

[Vincent Gerris (vgerris)]

hi, this machine has not been much customised. I only switched display manager because the supplied one did not work. I cannot reinstall and lose data.
Display link does not work on at least 2 of my systems with kernel 5.13 and they reopened a bug because I reported it - those drivers are always behind and rather unstable in my experience, especially with nouveau currently.

I hope devs can come up with a better answer because I bet a lot of folks will run into this issue.
I uninstalled caffeine, removed plugins from /usr/share and the problem remains.
I would say I am rather handy with Linux, that is why I run dev builds sometimes and report issues.
If I want buggy drivers and no support I can just install windows, man even macOS runs better on both machines.
Please notify the gdm3 devs and gnome-extensions ones, because stuff changed there.
You can also close the bug, but I am not gonna waste my time on finding the issue anymore then.
Isn´t the whole point of open source software that users make it better :)?

Also, I the time of reporting was right after the update, so it can´t be too hard to find.
This issue does not occur on another machine with a recent install of 20.04 and having that updated. That said, this machine certainly does not go further back than 18.04, I think actually 20.04 too.

How about we try to find the cause? You have not answered the question about where to find this plugins that are in the bug report, like xcaffeine.
thanks

[Vincent Gerris (vgerris)]

from the newly installed system with 20.04, warnings came for /var/lib/gdm3.config and .local not being empty.
root@ubuntu-inspiron-5482:/var/lib/gdm3# ls -lrta
total 32
drwxr-xr-x 3 root root 4096 feb 5 12:33 .config
drwx------ 3 gdm gdm 4096 feb 5 12:34 .nv
drwx------ 4 gdm gdm 4096 feb 5 12:35 .local
drwx------ 6 gdm gdm 4096 feb 5 12:35 .cache
drwxr-xr-x 101 root root 4096 feb 5 12:37 ..
-rw-r--r-- 1 gdm gdm 4444 feb 13 23:26 greeter-dconf-defaults
drwx--x--x 6 gdm gdm 4096 feb 13 23:26 .
is what that looks like on the broken system.

On the one with warning, it shows 755 instead of 700 permissions.
There is also no .nv dir.
I will wipe it out, reinstall and see what happens.

[Daniel van Vugt (vanvugt)]

> those drivers are always behind and rather unstable in my experience, especially with nouveau currently.

I was suggesting the 5.5 beta driver which is the latest (December 2021) - https://www.synaptics.com/products/displaylink-graphics/downloads/ubuntu. It works with the official jammy kernel 5.15. I know that because it's what I'm using in development.

Also please don't use the nouveau driver. It causes too many bugs so you should always stick to the Nvidia proprietary driver instead.

---

The next steps here are:

1. Enable debug mode in /etc/gdm3/custom.conf:

   [debug]
   Enable=true

2. Reboot and reproduce the no-login-screen problem again.

3. Reboot again, this time into recovery/safe mode and run:

   journalctl -b-1 > debugprevboot.txt

4. Attach the resulting text file here.

If you find the help you're getting here inadequate for any reason then you can also report the issue to GDM directly at:

  https://gitlab.gnome.org/GNOME/gdm/-/issues

If you do that then please let us know the new issue ID here.

[Vincent Gerris (vgerris)]

I tracked down the cause, it has to do with sssd and how gdm3 handles it.
Similar issue:
https://bugzilla.redhat.com/show_bug.cgi?id=1534873

First I removed kerberos auth, which did not seem to have had an effect.
Then I saw that fprintd was showing errors and fprintd-list was throwing the same error as in the logs.

I removed it and after that it worked.
So it seems like a bug in sssd related to fingerprint auth, when that is not working properly.

Regarding evdi - as you wrote, can be addressed separately. As I wrote , it does NOT work properly for me, not the beta driver, not even on 5.13 with beta driver. I just installed 5.12 kernel and latest release driver because the beta does not work properly on my system - I use a D6000 Dell dock.

Regarding this bug - I will try to see if I can get frintd to work. I still have Ubuntu sessions showing that do not work, not sure where they came from, this is even after I purged gnome gnome-shell and gnome-session. can login now with gdm3 and gnome session.

Is there anything else you need to pursue this ?

[Vincent Gerris (vgerris)]

confirmed that after reinstalling fprintd, the issue returns.
First of all, it creates a delay until the login screen loads.
then when the login screen loads, no user is visible to be clicked, also not after the 25000 ms timeout of the fprintd daemon.

So it seems the cause of the issue is the login process in gdm3 is not handling this properly - ideally the user would get a message like - fprintd error: timeout xxx.... etc and the login would skip fingerprint related stuff and go to normal login.

This is currently broken when the command fprintd-list times out like:
gnome-shell[2622]: Failed to connect to Fprint service: Error calling StartServiceByName for net.reactivated.Fprint: Timeout was reached

current work around:
drop to safe login and type:
apt remove fprintd
reboot

[Daniel van Vugt (vanvugt)]

Can you check to see if fprintd is:

 (a) still running and hung (RedHat issue 1534873); or
 (b) crashed (most likely bug 1960387)

If you can't find it still running then the steps to investigate crashes are https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment

[Vincent Gerris (vgerris)]

hi, it seems it does not start.
output from terminal:

ubuntu@ubuntu-inspiron-5482:~$ sudo apt install fprintd
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following NEW packages will be installed:
  fprintd
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/97,4 kB of archives.
After this operation, 680 kB of additional disk space will be used.
Selecting previously unselected package fprintd.
(Reading database ... 424549 files and directories currently installed.)
Preparing to unpack .../fprintd_1.94.1-1_amd64.deb ...
Unpacking fprintd (1.94.1-1) ...
Setting up fprintd (1.94.1-1) ...
fprintd.service is a disabled or a static unit not running, not starting it.
Processing triggers for dbus (1.12.20-2ubuntu2) ...
Processing triggers for man-db (2.10.1-1) ...
ubuntu@ubuntu-inspiron-5482:~$ systemctl restart fprintd.service
Job for fprintd.service failed because a fatal signal was delivered to the control process.
See "systemctl status fprintd.service" and "journalctl -xeu fprintd.service" for details.
ubuntu@ubuntu-inspiron-5482:~$ systemctl status fprintd.service
× fprintd.service - Fingerprint Authentication Daemon
     Loaded: loaded (/lib/systemd/system/fprintd.service; static)
     Active: failed (Result: signal) since Thu 2022-02-17 00:20:25 CET; 15s ago
       Docs: man:fprintd(1)
    Process: 33083 ExecStart=/usr/libexec/fprintd (code=killed, signal=SEGV)
   Main PID: 33083 (code=killed, signal=SEGV)
        CPU: 531ms

feb 17 00:20:23 ubuntu-inspiron-5482 systemd[1]: Starting Fingerprint Authentication Daemon...
feb 17 00:20:25 ubuntu-inspiron-5482 systemd[1]: fprintd.service: Main process exited, code=killed, status=11/SEGV
feb 17 00:20:25 ubuntu-inspiron-5482 systemd[1]: fprintd.service: Failed with result 'signal'.
feb 17 00:20:25 ubuntu-inspiron-5482 systemd[1]: Failed to start Fingerprint Authentication Daemon.
ubuntu@ubuntu-inspiron-5482:~$ journalctl -xeu fprintd.service
░░
░░ The job identifier is 2235.
feb 15 16:45:17 ubuntu-inspiron-5482 systemd[1]: fprintd.service: Main process exited, code=killed, status=11/SEGV
░░ Subject: Unit process exited
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ An ExecStart= process belonging to unit fprintd.service has exited.
░░
░░ The process' exit code is 'killed' and its exit status is 11.
feb 15 16:45:17 ubuntu-inspiron-5482 systemd[1]: fprintd.service: Failed with result 'signal'.
░░ Subject: Unit failed
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ The unit fprintd.service has entered the 'failed' state with result 'signal'.
feb 15 16:45:17 ubuntu-inspiron-5482 systemd[1]: Failed to start Fingerprint Authentication Daemon.
░░ Subject: A start job for unit fprintd.service has failed
░░ Defined-By: systemd
░░ Support: http://www.ubuntu.com/support
░░
░░ A start job for unit fprintd.service has finished with a failure.
░░
░░ The job identifier is 2235 and the job result is failed.

there is also a bug here : https://bugs.launchpad.net/ubuntu/+source/fprintd/+bug/1933633 that may be related?

Thanks for the heads up, hope these things will be solved.

St...

[Daniel van Vugt (vanvugt)]

Bug 1933633 is a clean exit whereas this bug 1960336 is a segfault. So the two bugs should be kept separate.

We can make this bug about both your issues though:
 (a) fprintd crashes with SIGSEGV; and
 (b) login screen can't survive fprintd failure.

Next please follow the steps in https://wiki.ubuntu.com/Bugs/Responses#Missing_a_crash_report_or_having_a_.crash_attachment to look for the fprintd crash.

[Daniel van Vugt (vanvugt)]

I am guessing the problem will be bug 1960387.

[Vincent Gerris (vgerris)]

Hi,

I think the most obvious is to have the fprintd bug tracked in the appropriate bug, and have this one track login not working.
I looked at the link and do not understand what you need.
There are some files in /var/crash that end in uploaded, I presume they are uploaded?

The last one for fprintd is attached here.

[Daniel van Vugt (vanvugt)]

Thanks for that: https://errors.ubuntu.com/oops/3e63925e-90a3-11ec-9112-fa163e983629
but it doesn't seem to be retraceable. Just bad luck. Maybe try crashing/reporting it again.

When we do eventually get a stack trace I think most likely the fprintd crash will move to bug 1960387, leaving this bug about gdm3 error handling only.

[Marco Trevisan (Treviño) (3v1n0)]

This is currently fixed, see: https://bugs.launchpad.net/ubuntu/+source/gnome-shell/+bug/1962566