Symptoms
Using GNOME desktop on 18.04 for a while now and everything has been working well. Upgraded to 18.10 yesterday and now stuck in a login loop.
I can solve the problem temporarily by CTRL + ALT + F3, logging in to the terminal and deleting my /home/user/.Xauthority file. Then returning to the greeter with ALT + -> and logging in works fine.
Once I reboot the machine the problem returns.
What Have I Tried
Looking at homedir permissions everything seems to be ok
$ls -lA | grep -E '.X|.ICE'
-rw------- 1 user user 1932 Oct 19 14:06 .ICEauthority
-rw------- 1 user user 52 Oct 19 14:06 .Xauthority
tmp permissions look ok
$ ls -ld /tmp
drwxrwxrwt 19 root root 12288 Oct 20 08:22 /tmp
Don't see anything bizarre in .xsession-errors
$ cat .xsession-errors
dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting XAUTHORITY=/home/user/.Xauthority
dbus-update-activation-environment: setting GTK_MODULES=gail:atk-bridge
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting CLUTTER_IM_MODULE=xim
dbus-update-activation-environment: setting LANG=en_US.UTF-8
dbus-update-activation-environment: setting GDM_LANG=en_US
dbus-update-activation-environment: setting DISPLAY=:0
dbus-update-activation-environment: setting GTK2_MODULES=overlay-scrollbar
dbus-update-activation-environment: setting MANDATORY_PATH=/usr/share/gconf/ubuntu.mandatory.path
dbus-update-activation-environment: setting XDG_GREETER_DATA_DIR=/var/lib/lightdm-data/user
dbus-update-activation-environment: setting USER=user
dbus-update-activation-environment: setting DESKTOP_SESSION=ubuntu
dbus-update-activation-environment: setting QT4_IM_MODULE=xim
dbus-update-activation-environment: setting DEFAULTS_PATH=/usr/share/gconf/ubuntu.default.path
dbus-update-activation-environment: setting QT_QPA_PLATFORMTHEME=appmenu-qt5
dbus-update-activation-environment: setting PWD=/home/user
dbus-update-activation-environment: setting HOME=/home/user
dbus-update-activation-environment: setting QT_ACCESSIBILITY=1
dbus-update-activation-environment: setting XDG_SESSION_TYPE=x11
dbus-update-activation-environment: setting XDG_DATA_DIRS=/usr/share/ubuntu:/usr/local/share:/usr/share:/var/lib/snapd/desktop:/var/lib/snapd/desktop
dbus-update-activation-environment: setting XDG_SESSION_DESKTOP=ubuntu
dbus-update-activation-environment: setting GTK_MODULES=gail:atk-bridge
dbus-update-activation-environment: setting SHELL=/bin/bash
dbus-update-activation-environment: setting XDG_SEAT_PATH=/org/freedesktop/DisplayManager/Seat0
dbus-update-activation-environment: setting QT_IM_MODULE=ibus
dbus-update-activation-environment: setting XMODIFIERS=@im=ibus
dbus-update-activation-environment: setting IM_CONFIG_PHASE=2
dbus-update-activation-environment: setting XDG_CURRENT_DESKTOP=ubuntu:GNOME
dbus-update-activation-environment: setting GPG_AGENT_INFO=/run/user/1000/gnupg/S.gpg-agent:0:1
dbus-update-activation-environment: setting SHLVL=1
dbus-update-activation-environment: setting LANGUAGE=en_US
dbus-update-activation-environment: setting GDMSESSION=ubuntu
dbus-update-activation-environment: setting LOGNAME=user
dbus-update-activation-environment: setting DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus
dbus-update-activation-environment: setting XDG_RUNTIME_DIR=/run/user/1000
dbus-update-activation-environment: setting XAUTHORITY=/home/user/.Xauthority
dbus-update-activation-environment: setting XDG_SESSION_PATH=/org/freedesktop/DisplayManager/Session2
dbus-update-activation-environment: setting XDG_CONFIG_DIRS=/etc/xdg/xdg-ubuntu:/etc/xdg
dbus-update-activation-environment: setting PATH=/home/user/bin:/home/user/.local/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games:/snap/bin
dbus-update-activation-environment: setting GTK_IM_MODULE=ibus
dbus-update-activation-environment: setting _=/usr/bin/dbus-update-activation-environment
LightDM reconfigure/remove/install
sudo dpkg-reconfigure lightdm
sudo apt-get purge lightdm
sudo apt-get install lightdm
Looked at lightdm logs and did not see anything there either.
From syslog I do notice this around the time I was logging in
Oct 19 14:01:27 computer systemd[1]: session-c1.scope: Killing process 2333 (lightdm) with signal SIGTERM.
Not sure what that is all about.
I am about out of ideas here so anyone have some more suggestions for what to try?
EDIT
Some more maybe helpful info. After reboot/login failure, followed by successful tty console login:
service lightdm status
● lightdm.service - Light Display Manager
Loaded: loaded (/lib/systemd/system/lightdm.service; indirect; vendor preset: enabled)
Drop-In: /lib/systemd/system/display-manager.service.d
└─xdiagnose.conf
Active: active (running) since Sat 2018-10-20 13:08:27 CDT; 1min 38s ago
Docs: man:lightdm(1)
Process: 1557 ExecStartPre=/bin/sh -c [ "$(basename $(cat /etc/X11/default-display-manager 2>/dev/null))" = "lightdm" ] (code=exited, status=0/SUCCESS)
Main PID: 1563 (lightdm)
Tasks: 26 (limit: 4915)
Memory: 74.6M
CGroup: /system.slice/lightdm.service
├─1563 /usr/sbin/lightdm
├─3530 /usr/lib/xorg/Xorg -core :0 -seat seat0 -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch
└─3748 lightdm --session-child 12 19
Oct 20 13:09:05 moltres lightdm[3560]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
Oct 20 13:09:05 moltres lightdm[3560]: PAM adding faulty module: pam_kwallet.so
Oct 20 13:09:05 moltres lightdm[3560]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open shared object file: No such file or directory
Oct 20 13:09:05 moltres lightdm[3560]: PAM adding faulty module: pam_kwallet5.so
Oct 20 13:09:05 moltres lightdm[3560]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0)
Oct 20 13:09:06 moltres lightdm[3748]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory
Oct 20 13:09:06 moltres lightdm[3748]: PAM adding faulty module: pam_kwallet.so
Oct 20 13:09:06 moltres lightdm[3748]: PAM unable to dlopen(pam_kwallet5.so): /lib/security/pam_kwallet5.so: cannot open shared object file: No such file or directory
Oct 20 13:09:06 moltres lightdm[3748]: PAM adding faulty module: pam_kwallet5.so
Oct 20 13:09:06 moltres lightdm[3748]: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "user"