LightDM：“身份validation失败”
在lightdm中输入登录信息后，屏幕会暂停黑白并再次返回登录屏幕。 但是，我可以毫无问题地通过TTY和gdm登录。
正如/var/log/lightdm/lightdm.log的日志文件所说，问题是“身份validation失败”，但我无法弄清楚如何解决它。
[+0.01s] DEBUG: Logging to /var/log/lightdm/lightdm.log [+0.01s] DEBUG: Starting Light Display Manager 1.4.0, UID=0 PID=2279 [+0.01s] DEBUG: Loaded configuration from /etc/lightdm/lightdm.conf [+0.01s] DEBUG: Using D-Bus name org.freedesktop.DisplayManager [+0.02s] DEBUG: Registered seat module xlocal [+0.03s] DEBUG: Registered seat module xremote [+0.03s] DEBUG: Adding default seat [+0.03s] DEBUG: Starting seat [+0.03s] DEBUG: Starting new display for greeter [+0.03s] DEBUG: Starting local X display [+0.03s] DEBUG: Using VT 7 [+0.03s] DEBUG: Activating VT 7 [+0.03s] DEBUG: Logging to /var/log/lightdm/x-0.log [+0.03s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0 [+0.03s] DEBUG: Launching X Server [+0.03s] DEBUG: Launching process 2287: /usr/bin/X :0 -core -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch [+0.03s] DEBUG: Waiting for ready signal from X server :0 [+0.03s] DEBUG: Acquired bus name org.freedesktop.DisplayManager [+0.03s] DEBUG: Registering seat with bus path /org/freedesktop/DisplayManager/Seat0 [+0.18s] DEBUG: Got signal 10 from process 2287 [+0.18s] DEBUG: Got signal from X server :0 [+0.18s] DEBUG: Connecting to XServer :0 [+0.18s] DEBUG: Starting greeter [+0.18s] DEBUG: Started session 2291 with service 'lightdm-greeter', username 'lightdm' [+0.22s] DEBUG: Session 2291 authentication complete with return value 0: Success [+0.22s] DEBUG: Greeter authorized [+0.22s] DEBUG: Logging to /var/log/lightdm/x-0-greeter.log [+0.25s] DEBUG: Session 2291 running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/unity-greeter [+0.65s] DEBUG: Greeter connected version=1.4.0 [+0.65s] DEBUG: Greeter connected, display is ready [+0.65s] DEBUG: New display ready, switching to it [+0.65s] DEBUG: Activating VT 7 [+3.16s] DEBUG: Greeter start authentication for amir [+3.16s] DEBUG: Started session 2383 with service 'lightdm', username 'amir' [+3.26s] DEBUG: Greeter start authentication for amir [+3.26s] DEBUG: Session 2383: Sending SIGTERM [+3.26s] DEBUG: Started session 2385 with service 'lightdm', username 'amir' [+3.26s] DEBUG: Session 2383 terminated with signal 15 [+3.26s] DEBUG: Session 2383 failed during authentication [+3.27s] DEBUG: Session 2385 got 1 message(s) from PAM [+3.27s] DEBUG: Prompt greeter with 1 message(s) [+8.48s] DEBUG: Continue authentication [+8.50s] DEBUG: Session 2385 authentication complete with return value 0: Success [+8.50s] DEBUG: Authenticate result for user amir: Success [+8.51s] DEBUG: User amir authorized [+8.52s] DEBUG: Greeter requests session xubuntu [+8.52s] DEBUG: Using session xubuntu [+8.52s] DEBUG: Stopping greeter [+8.52s] DEBUG: Session 2291: Sending SIGTERM [+8.76s] DEBUG: Session 2291 exited with return value 0 [+8.76s] DEBUG: Greeter quit [+8.77s] DEBUG: Dropping privileges to uid 1000 [+8.77s] DEBUG: Calling setresgid [+8.77s] DEBUG: Calling setresuid [+8.86s] DEBUG: Restoring privileges [+8.86s] DEBUG: Calling setresuid [+8.86s] DEBUG: Calling setresgid [+8.87s] DEBUG: Dropping privileges to uid 1000 [+8.87s] DEBUG: Calling setresgid [+8.87s] DEBUG: Calling setresuid [+8.87s] DEBUG: Writing /home/amir/.dmrc [+9.07s] DEBUG: Restoring privileges [+9.07s] DEBUG: Calling setresuid [+9.07s] DEBUG: Calling setresgid [+9.28s] DEBUG: Starting session xubuntu as user amir [+9.28s] DEBUG: Session 2385 running command /usr/sbin/lightdm-session startxfce4 [+9.29s] DEBUG: Registering session with bus path /org/freedesktop/DisplayManager/Session0 [+9.40s] DEBUG: Session 2385 exited with return value 1 [+9.40s] DEBUG: User session quit [+9.40s] DEBUG: Stopping display [+9.40s] DEBUG: Sending signal 15 to process 2287 [+10.19s] DEBUG: Process 2287 exited with return value 0 [+10.19s] DEBUG: X server stopped [+10.19s] DEBUG: Removing X server authority /var/run/lightdm/root/:0 [+10.19s] DEBUG: Releasing VT 7 [+10.19s] DEBUG: Display server stopped [+10.19s] DEBUG: Display stopped [+10.19s] DEBUG: Active display stopped, switching to greeter [+10.19s] DEBUG: Switching to greeter [+10.19s] DEBUG: Starting new display for greeter [+10.19s] DEBUG: Starting local X display [+10.19s] DEBUG: Using VT 7 [+10.19s] DEBUG: Logging to /var/log/lightdm/x-0.log [+10.19s] DEBUG: Writing X server authority to /var/run/lightdm/root/:0 [+10.19s] DEBUG: Launching X Server [+10.19s] DEBUG: Launching process 2494: /usr/bin/X :0 -core -auth /var/run/lightdm/root/:0 -nolisten tcp vt7 -novtswitch [+10.19s] DEBUG: Waiting for ready signal from X server :0 [+10.34s] DEBUG: Got signal 10 from process 2494 [+10.34s] DEBUG: Got signal from X server :0 [+10.34s] DEBUG: Connecting to XServer :0 [+10.34s] DEBUG: Starting greeter [+10.34s] DEBUG: Started session 2497 with service 'lightdm-greeter', username 'lightdm' [+10.36s] DEBUG: Session 2497 authentication complete with return value 0: Success [+10.36s] DEBUG: Greeter authorized [+10.36s] DEBUG: Logging to /var/log/lightdm/x-0-greeter.log [+10.36s] DEBUG: Session 2497 running command /usr/lib/lightdm/lightdm-greeter-session /usr/sbin/unity-greeter [+10.63s] DEBUG: Greeter connected version=1.4.0 [+10.63s] DEBUG: Greeter connected, display is ready [+10.63s] DEBUG: New display ready, switching to it [+10.63s] DEBUG: Activating VT 7 [+10.63s] DEBUG: Stopping greeter display being switched from [+10.92s] DEBUG: Greeter start authentication for amir [+10.92s] DEBUG: Started session 2582 with service 'lightdm', username 'amir' [+10.92s] DEBUG: Session 2582 got 1 message(s) from PAM [+10.92s] DEBUG: Prompt greeter with 1 message(s) [+11.20s] DEBUG: Greeter start authentication for amir [+11.20s] DEBUG: Session 2582: Sending SIGTERM [+11.20s] DEBUG: Started session 2584 with service 'lightdm', username 'amir' [+11.20s] DEBUG: Session 2582 terminated with signal 15 [+11.20s] DEBUG: Session 2582 failed during authentication [+11.21s] DEBUG: Session 2584 got 1 message(s) from PAM [+11.21s] DEBUG: Prompt greeter with 1 message(s) [+14.61s] DEBUG: Greeter closed communication channel [+59.09s] DEBUG: Continue authentication [+59.11s] DEBUG: Got signal 15 from process 1 [+59.11s] DEBUG: Caught Terminated signal, shutting down [+59.11s] DEBUG: Stopping display manager [+59.11s] DEBUG: Stopping seat [+59.11s] DEBUG: Stopping display [+59.11s] DEBUG: Session 2497: Sending SIGTERM [+59.11s] DEBUG: Session 2584 terminated with signal 15 [+59.11s] DEBUG: Session 2584 failed during authentication [+59.11s] DEBUG: Authenticate result for user amir: Authentication stopped before completion [+59.23s] DEBUG: Greeter closed communication channel [+59.23s] DEBUG: Session 2497 exited with return value 0 [+59.23s] DEBUG: Greeter quit [+59.23s] DEBUG: Sending signal 15 to process 2494 [+59.25s] DEBUG: Process 2494 exited with return value 0 [+59.25s] DEBUG: X server stopped [+59.25s] DEBUG: Removing X server authority /var/run/lightdm/root/:0 [+59.25s] DEBUG: Releasing VT 7 [+59.25s] DEBUG: Display server stopped [+59.25s] DEBUG: Display stopped [+59.25s] DEBUG: Seat stopped [+59.25s] DEBUG: Display manager stopped [+59.25s] DEBUG: Stopping daemon [+59.25s] DEBUG: Exiting with return value 0
主目录中有一个名为.Xauthority的文件。 将此文件的所有者和组从root更改为用户，并将权限更改为664解决了该问题。