Hello,
It happened a few times already, randomly. I'm working on my XFCE4 desktop, not reproducible, and suddenly I see my sddm login screen, I was logged out. It also happened with lightdm DM, so it's not sddm.
The logs tell almost nothing, the precise time was 11:48:21:095
sddm.log:
[11:28:46.056] (II) DAEMON: Session started
[11:48:21.095] (II) HELPER: [PAM] Closing session
[11:48:21.097] (II) HELPER: [PAM] Ended.
[11:48:21.098] (II) DAEMON: Auth: sddm-helper exited successfully
[11:48:21.098] (II) DAEMON: Socket server stopping...
[11:48:21.098] (II) DAEMON: Socket server stopped.
[11:48:21.098] (II) DAEMON: Display server stopping...
[11:48:22.295] (II) DAEMON: Display server stopped.
[11:48:22.295] (II) DAEMON: Running display stop script "/usr/share/sddm/scripts/Xstop"
[11:48:22.298] (II) DAEMON: Removing display ":0" ...
[11:48:22.299] (II) DAEMON: Adding new display on vt 7 ...
[11:48:22.299] (II) DAEMON: Loading theme configuration from ""
[11:48:22.299] (II) DAEMON: Display server starting...
[11:48:22.299] (II) DAEMON: Running: /usr/bin/X -nolisten tcp -auth /var/run/sddm/{9abd59b6-6491-40fb-b700-0d5c322cf310} -background none -noreset -displayfd 19 -seat seat0 vt7
[11:48:23.218] (II) DAEMON: Setting default cursor
[11:48:23.226] (II) DAEMON: Running display setup script "/usr/share/sddm/scripts/Xsetup"
Xorg.0.log, only tail; nothing here, I think.
[ 18.660] (II) event15 - (II) Logitech M570: (II) is tagged by udev as: Mouse Trackball
[ 18.660] (II) event15 - (II) Logitech M570: (II) device set to 540 DPI
[ 18.660] (II) event15 - (II) Logitech M570: (II) device is a pointer
messages.log: suspicious bluetoothd log at 11:48:21 is always present when this happens, is it the trigger?
Nov 1 11:44:57 beluga nm-dispatcher[8301]: req:1 'dhcp4-change' [wlan0]: start running ordered scripts...
Nov 1 11:48:21 beluga bluetoothd[4464]: Endpoint unregistered: sender=:1.39 path=/MediaEndpoint/A2DPSource
Nov 1 11:48:21 beluga bluetoothd[4464]: Endpoint unregistered: sender=:1.39 path=/MediaEndpoint/A2DPSink
Nov 1 11:48:22 beluga acpid[4258]: client 4440[0:0] has disconnected
Nov 1 11:48:22 beluga acpid[4258]: client 4440[0:0] has disconnected
Nov 1 11:48:22 beluga acpid[4258]: client connected from 8387[0:0]
Nov 1 11:48:22 beluga acpid[4258]: 1 client rule loaded
Nov 1 11:48:22 beluga acpid[4258]: client connected from 8387[0:0]
Nov 1 11:48:22 beluga acpid[4258]: 1 client rule loaded
Nov 1 11:48:50 beluga rtkit-daemon[7588]: Successfully made thread 8503 of process 8503 (/usr/bin/pulseaudio) owned by '1000' high priority at nice level -11.
Nov 1 11:48:50 beluga bluetoothd[4464]: Endpoint registered: sender=:1.62 path=/MediaEndpoint/A2DPSource
Nov 1 11:48:50 beluga bluetoothd[4464]: Endpoint registered: sender=:1.62 path=/MediaEndpoint/A2DPSink
Nov 1 11:48:50 beluga dbus[3470]: [system] Activating service name='org.blueman.Mechanism' (using servicehelper)
Nov 1 11:48:51 beluga blueman-mechanism[8627]: Starting blueman-mechanism
Nov 1 11:48:51 beluga dbus[3470]: [system] Successfully activated service 'org.blueman.Mechanism'
Nov 1 11:48:51 beluga blueman-mechanism[8627]: loading Ppp
Nov 1 11:48:51 beluga blueman-mechanism[8627]: loading Rfcomm
Nov 1 11:48:51 beluga blueman-mechanism[8627]: loading RfKill
Nov 1 11:48:51 beluga blueman-mechanism[8627]: loading Network
Nov 1 11:49:07 beluga dhclient[7369]: DHCPREQUEST on wlan0 to 192.168.1.2 port 67
Nov 1 11:49:07 beluga dhclient[7369]: DHCPACK from 192.168.1.2
daemon.log (same comments as above)
Nov 1 11:44:57 beluga nm-dispatcher[8301]: req:1 'dhcp4-change' [wlan0]: startrunning ordered scripts...
Nov 1 11:48:21 beluga bluetoothd[4464]: Endpoint unregistered: sender=:1.39 path=/MediaEndpoint/A2DPSource
Nov 1 11:48:21 beluga bluetoothd[4464]: Endpoint unregistered: sender=:1.39 path=/MediaEndpoint/A2DPSink
Nov 1 11:48:21 beluga kernel: udevd[615]: RUN{builtin}: 'uaccess' unknown /usr/lib/udev/rules.d/73-seat-late.rules:15
Nov 1 11:48:22 beluga acpid[4258]: client 4440[0:0] has disconnected
Nov 1 11:48:22 beluga acpid[4258]: client 4440[0:0] has disconnected
Nov 1 11:48:22 beluga acpid[4258]: client connected from 8387[0:0]
Nov 1 11:48:22 beluga acpid[4258]: 1 client rule loaded
Nov 1 11:48:22 beluga acpid[4258]: client connected from 8387[0:0]
Nov 1 11:48:22 beluga acpid[4258]: 1 client rule loaded
Nov 1 11:48:50 beluga rtkit-daemon[7588]: Successfully made thread 8503 of process 8503 (/usr/bin/pulseaudio) owned by '1000' high priority at nice level -11.
Nov 1 11:48:50 beluga rtkit-daemon[7588]: Supervising 1 threads of 1 processes of 1 users.
auth.log, something suspicious here as well:
Nov 1 11:28:46 beluga polkitd[4169]: Registered Authentication Agent for unix-session:c2 (system bus name :1.30 [/usr/lib/polkit-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_GB.UTF-8)
Nov 1 11:48:21 beluga polkitd[4169]: Unregistered Authentication Agent for unix-session:c2 (system bus name :1.30, object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_GB.UTF-8) (disconnected from bus)
Nov 1 11:48:21 beluga sddm-helper[7484]: pam_unix(sddm:session): session closed for user myuser
Nov 1 11:48:21 beluga kernel: elogind[3504]: Removed session c2.
Nov 1 11:48:21 beluga kernel: elogind[3504]: Failed to remove runtime directory /run/user/1000: Permission denied
Nov 1 11:48:23 beluga sddm-helper[8396]: pam_unix(sddm-greeter:session): session opened for user sddm by (uid=0)
Nov 1 11:48:23 beluga kernel: elogind[3504]: New session c3 of user sddm.
The other logs don't add anything, I think.
This is my daily use laptop so I must fix this fast. So, any help will be much appreciated.