Created attachment 1871628 [details]
journal from a boot when the sddm logout problem happened

Description of problem:

I was using a Fedora 36 KDE Plasma installation. sddm on Wayland with kwin_wayland as a compositor from sddm-0.19.0^git20220321.e67307e-2.fc36.x86_64 and sddm-wayland-plasma-5.24.4-1.fc36.noarch was used. A text login prompt on VT2 sometimes appeared instead of sddm on Wayland when logging out of Plasma 5.24.4 on Wayland. The problem seemed to start around the update to sddm-0.19.0^git20220321.e67307e-2.fc36 or sddm-0.19.0^git20220321.e67307e-1.fc36. This problem happened about 15 times since 2022-4-4 according to the journal. The message sddm[971]: Auth: sddm-helper exited with 3 was shown in the journal when the problem occurred which seemed to indicate that sddm-helper exited abnormally during the logout process.

Apr 09 19:35:02 systemd[1]: Started user - User Manager for UID 989.
Apr 09 19:35:02 audit[1]: SERVICE_START pid=1 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0 msg='unit=user@989 comm="systemd" exe="/usr/lib/systemd/systemd" hostname=? addr=? terminal=? res=success'
Apr 09 19:35:02 systemd[1]: Started session-c2.scope - Session c2 of User sddm.
Apr 09 19:35:02 audit[2789]: USER_START pid=2789 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='op=PAM:session_open grantors=pam_unix,pam_systemd acct="sddm" exe="/usr/libexec/sddm-helper" hostname=localhost.localdomain addr=? terminal=/dev/tty2 res=success'
Apr 09 19:35:02 kernel: fbcon: Taking over console
Apr 09 19:35:02 sddm-helper[2789]: pam_unix(sddm-greeter:session): session closed for user sddm
Apr 09 19:35:02 audit[2789]: USER_END pid=2789 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='op=PAM:session_close grantors=pam_unix,pam_systemd acct="sddm" exe="/usr/libexec/sddm-helper" hostname=localhost.localdomain addr=? terminal=/dev/tty2 res=success'
Apr 09 19:35:02 audit[2789]: CRED_DISP pid=2789 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:xdm_t:s0-s0:c0.c1023 msg='op=PAM:setcred grantors=pam_permit acct="sddm" exe="/usr/libexec/sddm-helper" hostname=localhost.localdomain addr=? terminal=/dev/tty2 res=success'
Apr 09 19:35:02 systemd[1]: session-c2.scope: Deactivated successfully.
Apr 09 19:35:02 sddm[971]: Auth: sddm-helper exited with 3
Apr 09 19:35:02 systemd-logind[862]: Session c2 logged out. Waiting for processes to exit.
Apr 09 19:35:02 systemd-logind[862]: Removed session c2.

I guess sddm on Wayland didn't appear as a result of the sddm-helper problem. Logging in to the text prompt and running sudo systemctl restart sddm always resulted in sddm not appearing and the same sddm-helper error message.

Version-Release number of selected component (if applicable):
sddm-0.19.0^git20220321.e67307e-2.fc36.x86_64
sddm-wayland-plasma-5.24.4-1.fc36.noarch
plasma-workspace-5.24.4-1.fc36.x86_64
kf5-plasma-5.91.0-1.fc36.x86_64
qt5-qtbase-5.15.3-1.fc36.x86_64

How reproducible:
This problem happened about 30-50% when logging out of Plasma on Wayland using sddm on Wayland from sddm-0.19.0^git20220321.e67307e-2.fc36

Steps to Reproduce:
1. Boot a Fedora 36 KDE Plasma installation updated to 2022-4-9 with updates-testing enabled. sddm-wayland-plasma-5.24.4-1.fc36.noarch and sddm-0.19.0^git20220321.e67307e-2.fc36.x86_64 must be installed.
2. Log in to Plasma 5.24.4 on Wayland from sddm on Wayland
3. Log out of Plasma
4. If the problem didn't happen, repeat 2-3 until it does.

Actual results:
A text login prompt on VT2 sometimes appeared instead of sddm on Wayland when logging out of Plasma.

Expected results:
sddm on Wayland would appear every time when logging out of Plasma.

Additional info:
I noticed when logging out of Plasma on Wayland many KDE programs had errors like "The Wayland connection broke. Did the Wayland compositor die?". I'm unsure if those errors are related to this problem. I'll attach the journal from a boot when the problem happened.