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Hey all,
every once in a while (not often, maybe twice a year) it happens that I cannot unlock/login after waking my system up from suspend.
I can normally type my session unlock password to the LightDM greeter but after pressing "unlock" nothing will happen
(the greeter seems to freeze for a while). I can still switch to another TTY and type username/password but cannot
actually login there either (also freezes for a while). After a reboot everything is back to normal.
The problem is that there is nothing helpful in the journal. If I compare to a successful suspend/wakeup cycle the only real
difference is that the following lines are missing in journalctl (which is no surprise as it fails to switch back to the running session):
systemd[1]: Stopping Session cX of User lightdm...
lightdm[...]: pam_unix(lightdm-greeter:session): session closed for user lightdm
systemd[1]: session-cX.scope: Deactivated successfully.
systemd[1]: Stopped Session cX of User lightdm.
systemd-logind[...]: Removed session cX.Because the overall system does not really freeze and login via TTY is also affected I suppose that this problem is perhaps somehow related to PAM, though.
Does anyone know what could go wrong here? As I said, this problem rarely happens and thus I cannot really reproduce or debug it.
Concerning the logs: is there any way for me to provide some useful logs the next time this might happen (without having to have debug level logs for half a year...)?
Also, this time I rebooted using SysRq without trying anything else first; would it make any difference for the journal completeness if I tried e.g. a Ctrl+Alt+Del from tty1 or so?
System configuration:
Display server: Xorg
Display manager: LightDM
Desktop environment: Xfce
Screen locker: light-locker
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