Lightdm infinite login loop

After yesterdays system update I have a problem with an infinite login loop.

What I have tried so far without success:

  • followed the hints of the lightdm wiki
  • reinstalled lightdm
  • removed the second monitor
  • looked into systemctl status - ok, no errors
  • looked into /var/log/lightdm/lightdm.log:
[+10.66s] DEBUG: Session pid=1704: Started with service 'lightdm', username 'uli'
[+10.68s] DEBUG: Session pid=1704: Got 1 message(s) from PAM
[+10.68s] DEBUG: Prompt greeter with 1 message(s)
[+14.82s] DEBUG: Seat seat0 changes active session to
[+21.00s] DEBUG: Seat seat0 changes active session to 4
[+280.70s] DEBUG: Seat seat0 changes active session to c2
[+280.70s] DEBUG: Session c2 is already active
[+285.04s] DEBUG: Continue authentication
[+285.06s] DEBUG: Session pid=1704: Authentication complete with return value 0: Success
[+285.06s] DEBUG: Authenticate result for user uli: Success
[+285.06s] DEBUG: User uli authorized
[+285.07s] DEBUG: Greeter sets language de_DE.utf8
[+285.14s] DEBUG: Greeter requests session xfce
[+285.14s] DEBUG: Seat seat0: Stopping greeter; display server will be re-used for user session
[+285.14s] DEBUG: Terminating login1 session c2
[+285.14s] DEBUG: Session pid=1681: Sending SIGTERM
[+285.16s] DEBUG: Greeter closed communication channel
[+285.16s] DEBUG: Session pid=1681: Exited with return value 0
[+285.16s] DEBUG: Seat seat0: Session stopped
[+285.16s] DEBUG: Seat seat0: Greeter stopped, running session
[+285.16s] DEBUG: Registering session with bus path /org/freedesktop/DisplayManager/Session1
[+285.16s] DEBUG: Session pid=1704: Running command /etc/lightdm/Xsession startxfce4
[+285.16s] DEBUG: Creating shared data directory /var/lib/lightdm-data/uli
[+285.16s] DEBUG: Session pid=1704: Logging to .xsession-errors
[+285.22s] DEBUG: Activating VT 7
[+285.22s] DEBUG: Activating login1 session 5
[+285.22s] DEBUG: Seat seat0 changes active session to
[+285.22s] DEBUG: Seat seat0 changes active session to 5
[+285.22s] DEBUG: Session 5 is already active
[+285.37s] DEBUG: Session pid=1704: Exited with return value 127
[+285.37s] DEBUG: Seat seat0: Session stopped
[+285.37s] DEBUG: Seat seat0: Stopping display server, no sessions require it
[+285.37s] DEBUG: Sending signal 15 to process 1667
[+285.41s] DEBUG: Seat seat0 changes active session to
[+285.71s] DEBUG: Process 1667 exited with return value 0
[+285.71s] DEBUG: XServer 0: X server stopped

looking into ~/.xsession-errors I find:

xfce4-session: symbol lookup error: xfce4-session: undefined symbol: xfce4_screensaver_lock

Installing xfce4_screensaver did not help.
df shows 30% disk space used.

journalctl -b | grep lightdm reveals a suspect message:

Feb 21 10:47:51 BigBox lightdm[1536]: pam_unix(lightdm:session): session opened for user uli(uid=1000) by (uid=0)
Feb 21 10:47:51 BigBox lightdm[1536]: gkr-pam: unlocked login keyring
Feb 21 10:47:51 BigBox audit[1536]: USER_START pid=1536 uid=0 auid=1000 ses=3 subj=unconfined msg='op=PAM:session_open grantors=pam_loginuid,pam_keyinit,pam_systemd_home,pam_limits,pam_unix,pam_permit,pam_mail,pam_systemd,pam_env,pam_gnome_keyring acct="uli" exe="/usr/bin/lightdm" hostname=? addr=? terminal=:0 res=success'
Feb 21 10:47:51 BigBox lightdm[1536]: Failed to write utmpx: No such file or directory
Feb 21 10:47:51 BigBox audit[1536]: USER_LOGIN pid=1536 uid=0 auid=1000 ses=3 subj=unconfined msg='op=login id=1000 exe="/usr/bin/lightdm" hostname=BigBox addr=? terminal=/dev/tty7 res=success'
Feb 21 10:47:52 BigBox lightdm[1536]: Failed to write utmpx: No such file or directory
Feb 21 10:47:52 BigBox audit[1536]: USER_LOGOUT pid=1536 uid=0 auid=1000 ses=3 subj=unconfined msg='op=logout id=1000 exe="/usr/bin/lightdm" hostname=BigBox addr=? terminal=/dev/tty7 res=success'
Feb 21 10:47:52 BigBox lightdm[1536]: pam_unix(lightdm:session): session closed for user uli

(Failed to write utmpx)

What else can I do? Any hint is very much appreciated.

ok, I found a workaround: I downgraded xfce4-session from 4.18.1 to 4.18.0. With this, login is working again and the xsession eror does not appear.

Same here. Also problem with Xfce4 Power Manager

xfce4-power-manager: symbol lookup error: xfce4-power-manager: undefined symbol: xfce_screensaver_lock

Downgrading both to 1.18.0-1 helps, for the moment.

Possible solution here :

Looks like the true solution for this problem. Thanks. Fully upgraded now.

Out of curiosity, what was the original reason for installing libxfce4ui-devel from the AUR instead of keeping libxfce4ui from the Manjaro supported repositories?

I know a couple of updates ago there was the issue with libxfce4ui-nocsd and those using it were instructed to revert to the regular package libxfce4ui. It was listed in the “Known issues and solutions” of the Stable Update Announcment.

Never had the notion of this library until now. I think my Xfce installation originates from its original Manjaro install moment somewhere a year ago and worked flawlessly until this moment. Version of libxfce4ui-devel is a little bit behind of libxfce4ui, so it could be expected that this was a possible solution.