SDDM freezes on system boot

[Mauro Gaspari]

System Info:
OS: Ubuntu Studio Groovy Gorilla
Description: Ubuntu Groovy Gorilla (development branch)
Release: 20.10
Kernel: 5.8.0-16-lowlatency
CPU: AMD Ryzen 7 2700X (16) @ 3.700GHz
GPU: AMD ATI Radeon VII

Package Info:
sddm:
  Installed: 0.18.1-1ubuntu3
  Candidate: 0.18.1-1ubuntu3
  Version table:
 *** 0.18.1-1ubuntu3 500
        500 http://archive.ubuntu.com/ubuntu groovy/universe amd64 Packages
        100 /var/lib/dpkg/status

What I expect to happen:
After computer completes boot, I expect to be able to select my user, enter my password and login successfully in Plasma Desktop.

What happened instead:
After computer completes boot, SDDM appears to be frozen. Cursor does not blink in the password field, as it should. Mouse still moves but cannot click any icon. System is not frozen, I can drop to another tty, login, check logs, reboot.
This does not happen every time I boot, I have not yet found a way to reproduce the issue reliably, but I would say it happens around 30%~50% of the times I boot.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: sddm 0.18.1-1ubuntu3
ProcVersionSignature: Ubuntu 5.8.0-16.17-lowlatency 5.8.0
Uname: Linux 5.8.0-16-lowlatency x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu45
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: KDE
Date: Fri Aug 28 12:19:46 2020
InstallationDate: Installed on 2020-07-14 (44 days ago)
InstallationMedia: Ubuntu-Studio 20.10 "Groovy Gorilla" - Alpha amd64 (20200712)
SourcePackage: sddm
UpgradeStatus: No upgrade log present (probably fresh install)

[Mauro Gaspari (ilvipero)]

Attaching logs:
In the attached logs you can see 2 reboots:
08:23 - this boot completes successfully, I was able to login and use the system.
11:51 - this boot has the issue reported.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Lassi (lassi-vaatamoinen)]

Has been happening to me on several occasions. Caught logs just now.

SDDM seems fine at first for 3-4 seconds, but then the blinking cursor from the password entry box disappears. Only mouse cursor moving in SDDM greeter screen, but no interaction with any UI elements.

Can switch between virtual terminals.

In the attached logs it can be seen that the error happened at around 17:15 and 17:18-17:19.
Successful SDDM session at 17:27.

Seems that the following entry in syslog may be related, as it happens just within the time frame when the text cursor disappears:

Dec 5 17:19:02 kaappi sddm-helper[1637]: [PAM] Closing session
Dec 5 17:19:02 kaappi sddm-helper[1637]: [PAM] Ended.
Dec 5 17:19:02 kaappi systemd[1]: session-1.scope: Succeeded.
Dec 5 17:19:02 kaappi sddm[1513]: Auth: sddm-helper exited with 9
Dec 5 17:19:02 kaappi sddm[1513]: Greeter stopped.

And that is present on both failing occasions (17:15 and 17:19). On the last SDDM (re)start (17:27) there is no such log entry.

[Matt Mayfield (mdmayfield)]

Same symptoms here, same syslog message whenever the issue occurs ("Auth: sddm-helper exited with 9").

I'm on a Dell XPS 15 7590 with Ubuntu Studio 21.04 development/alpha/daily, all packages up to date. Prior to this installation I was running Ubuntu MATE 20.04 and never saw this issue, but of course Ubuntu MATE does not use SDDM.

[Marco (marco93)]

I'm on UbuntuStudio 20.04 and had similar issues with lightdm I then switched to sddm and exactly run into the same bug sporadically:

Nov 01 14:33:09 marco sddm-greeter[1127]: Message received from daemon: Capabilities
Nov 01 14:33:09 marco sddm-greeter[1127]: Message received from daemon: HostName
Nov 01 14:33:12 marco sddm-helper[1114]: [PAM] Closing session
Nov 01 14:33:12 marco sddm-helper[1114]: pam_unix(sddm-greeter:session): session closed for user sddm
Nov 01 14:33:12 marco sddm-helper[1114]: [PAM] Ended.
Nov 01 14:33:12 marco sddm[1007]: Auth: sddm-helper exited with 9
Nov 01 14:33:12 marco sddm[1007]: Greeter stopped.

The mouse still works but the sddm screen is basically unresponsive.

Is there any news on this?

[Lassi (lassi-vaatamoinen)]

Ubuntu Studio 21.10: issue still present.

5.13.0-23-lowlatency #23-Ubuntu SMP PREEMPT Fri Nov 26 14:14:06 UTC 2021 x86_64 x86_64 x86_64 GNU/Linux

SDDM greeter screen goes pitch black after a few seconds. Mouse cursor can be moved.

Workaround: Need to login to another TTY and execute 'sudo service sddm restart'

[Lassi (lassi-vaatamoinen)]

Still valid for Ubuntu Studio 22.04.1 LTS.

[Slalomsk8er (slalomsk8er)]

Still see the same problem with Ubuntu Studio 22.04.1 LTS.
In my case it looks like I can reproduce it just by waiting.
So if I boot and make a coffee I can't login but if I then reboot and login immediately, all is fine.

Nov 12 09:26:13 hostname sddm[1676]: Greeter starting...
...
/var/log/syslog:Nov 12 09:26:15 hostname sddm-greeter[1706]: Adding view for "HDMI-3" QRect(0,0 1920x1080)
/var/log/syslog:Nov 12 09:26:17 hostname sddm-greeter[1706]: Hunspell dictionary is missing for "de_DE" . Search paths ("/usr/share/qt5/qtvirtualkeyboard/hunspell", "/usr/share/hunspell", "/usr/share/myspell/dicts")
/var/log/syslog:Nov 12 09:26:17 hostname sddm-greeter[1706]: Message received from daemon: Capabilities
/var/log/syslog:Nov 12 09:26:17 hostname sddm-greeter[1706]: Message received from daemon: HostName
/var/log/syslog:Nov 12 09:26:19 hostname sddm-helper[1693]: [PAM] Closing session
/var/log/syslog:Nov 12 09:26:19 hostname sddm-helper[1693]: [PAM] Ended.
/var/log/syslog:Nov 12 09:26:19 hostname sddm[1676]: Auth: sddm-helper exited with 9
/var/log/syslog:Nov 12 09:26:19 hostname sddm[1676]: Greeter stopped.

will now try to install the missing hunspell dictionary and see if things still fail.

[Major Oversight (majoroversight)]

I suddenly started experiencing this issue on Kubuntu 22.04.1 a few months after upgrading from 20.04 LTS. After almost a month of frustration, I discovered that pam was closing unexpectedly, causing the greeter to stop, and that that was the reason that sddm became unresponsive.

I came upon a workaround suggested in github sddm issue #1443:

loginctl enable-linger

Using this appears to prevent pam from closing out.

I hope that the cause of pam closing out can be found, or that sddm is updated to detect that the greeter has stopped without a user logging in.

Edit: forgot to ask whether pam closing is a systemd / loginctl issue?

[Major Oversight (majoroversight)]

With some recent SDDM updates, I started experiencing this intermittently despite enabling linger.
After digging around for a while, the commenting out the following lines in /usr/lib/systemd/system/sddm.service seems to have cured the issue:

# Ordering
#Conflicts=plymouth-quit-wait.service
#After=systemd-user-sessions.service plymouth-start.service plymouth-quit-wait.service plymouth-quit.service systemd-logind.service
#OnFailure=plymouth-quit.service

These lines have to be commented out each time SDDM is updated as the service file is replaced with a new version that uncomments those lines. I am guessing that these line were added by Ubuntu/Kubuntu as the sddm.service is somewhat different from what I could find on the project page (https://github.com/sddm/sddm/blob/develop/services/sddm.service.in)?

I still have "loginctl enable-linger sddm" in place, so need to test whether disabling linger causes the issue to return with those lines in sddm.service commented out.

[Sebastian K. (seba-k)]

Thank you for sharing @majoroversight.

I experience the same issue on Ubuntu Studio 22.04.2.

Operating System: Ubuntu Studio 22.04
KDE Plasma Version: 5.24.7
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3
Kernel Version: 5.19.0-1023-lowlatency (64-bit)
Graphics Platform: X11
Processors: 12 × AMD Ryzen 5 1600X Six-Core Processor
Memory: 15.6 GiB of RAM
Graphics Processor: NVIDIA GeForce RTX 3060/PCIe/SSE2

Will try your workaround if the issue persists.

[Hans P. Möller (hmollercl)]

I commented the lines

# Ordering
#Conflicts=plymouth-quit-wait.service
#After=systemd-user-sessions.service plymouth-start.service plymouth-quit-wait.service plymouth-quit.service systemd-logind.service
#OnFailure=plymouth-quit.service

but problem is still happening

[Hans P. Möller (hmollercl)]

This is the output of
$systemctl status sddm

* sddm.service - Simple Desktop Display Manager
     Loaded: loaded (/lib/systemd/system/sddm.service; enabled; vendor preset: enabled)
     Active: active (running) since Wed 2023-10-11 20:59:11 -03; 1min 9s ago
       Docs: man:sddm(1)
             man:sddm.conf(5)
    Process: 936 ExecStartPre=/bin/sh -c [ "$(cat /etc/X11/default-display-manager 2>/dev/null)" = "/usr/bin/sddm" ] (code=exited, status=0/SUCCESS)
   Main PID: 939 (sddm)
      Tasks: 14 (limit: 18865)
     Memory: 174.7M
        CPU: 1.393s
     CGroup: /system.slice/sddm.service
             |-939 /usr/bin/sddm
             `-959 /usr/lib/xorg/Xorg -nolisten tcp -auth /var/run/sddm/{cea26b6b-64ec-4722-a88c-f3fab0a38281} -background none -noreset -displayfd 17 -seat seat0 vt1

Oct 11 20:59:15 hmoller-Inspiron-3458 sddm[939]: Loading theme configuration from "/usr/share/sddm/themes/ubuntu-theme/theme.conf"
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm[939]: Greeter starting...
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm-helper[1299]: [PAM] Starting...
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm-helper[1299]: [PAM] Authenticating...
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm-helper[1299]: [PAM] returning.
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm-helper[1299]: pam_unix(sddm-greeter:session): session opened for user sddm(uid=119) by (uid=0)
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm[939]: Greeter session started successfully
Oct 11 20:59:15 hmoller-Inspiron-3458 sddm[939]: Message received from greeter: Connect
Oct 11 20:59:20 hmoller-Inspiron-3458 sddm[939]: Auth: sddm-helper exited with 9
Oct 11 20:59:20 hmoller-Inspiron-3458 sddm[939]: Greeter stopped.

[Hans P. Möller (hmollercl)]

EDIT: This did not fix the issue

currently testing this, I will update as soon as I have another issue or when enough time have passed without

create a custom file: snap-apps.sh
In directory ~/.config/plasma-workspace/env
In the file write down:

export XDG_DATA_DIRS="$XDG_DATA_DIRS:/var/lib/snapd/desktop/"

Save the file and make it executable with:
sudo chmod +x snap-apps.sh

found on:
https://www.reddit.com/r/Kubuntu/comments/11alzdb/kubuntu_2004_lts_to_2204_upgrade_caused_freeze_of/