I have checked auth.log and found something interesting. When everything is OK, the log looks like this
Jul 15 18:11:02 weihong-pc systemd-logind[870]: New seat seat0. Jul 15 18:11:03 weihong-pc systemd-logind[870]: Watching system buttons on /dev/input/event1 (Power Button) Jul 15 18:11:03 weihong-pc systemd-logind[870]: Watching system buttons on /dev/input/event10 (Video Bus) Jul 15 18:11:03 weihong-pc systemd-logind[870]: Watching system buttons on /dev/input/event0 (Power Button) Jul 15 18:11:05 weihong-pc lightdm: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory Jul 15 18:11:05 weihong-pc lightdm: PAM adding faulty module: pam_kwallet.so Jul 15 18:11:05 weihong-pc lightdm: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0) Jul 15 18:11:05 weihong-pc systemd-logind[870]: New session c1 of user lightdm. Jul 15 18:11:05 weihong-pc systemd-logind[870]: Linked /tmp/.X11-unix/X0 to /run/user/104/X11-display. Jul 15 18:11:05 weihong-pc lightdm: pam_ck_connector(lightdm-greeter:session): nox11 mode, ignoring PAM_TTY :0 Jul 15 18:11:08 weihong-pc lightdm: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory Jul 15 18:11:08 weihong-pc lightdm: PAM adding faulty module: pam_kwallet.so Jul 15 18:11:08 weihong-pc lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "weihong" Jul 15 18:11:08 weihong-pc dbus[754]: [system] Rejected send message, 7 matched rules; type="method_return", sender=":1.25" (uid=0 pid=1450 comm="/usr/sbin/dnsmasq --no-resolv --keep-in-foreground") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.5" (uid=0 pid=939 comm="NetworkManager ") Jul 15 18:11:12 weihong-pc lightdm: pam_unix(lightdm-greeter:session): session closed for user lightdm Jul 15 18:11:12 weihong-pc lightdm: pam_unix(lightdm:session): session opened for user weihong by (uid=0) Jul 15 18:11:12 weihong-pc systemd-logind[870]: New session c2 of user weihong. Jul 15 18:11:12 weihong-pc systemd-logind[870]: Linked /tmp/.X11-unix/X0 to /run/user/1000/X11-display. Jul 15 18:11:12 weihong-pc lightdm: pam_ck_connector(lightdm:session): nox11 mode, ignoring PAM_TTY :0 Jul 15 18:11:14 weihong-pc gnome-keyring-daemon[1622]: Gkm: using old keyring directory: /home/weihong/.gnome2/keyrings Jul 15 18:11:14 weihong-pc gnome-keyring-daemon[1622]: Gkm: using old keyring directory: /home/weihong/.gnome2/keyrings Jul 15 18:11:14 weihong-pc gnome-keyring-daemon[1622]: couldn't set environment variable in session: The name org.gnome.SessionManager was not provided by any .service files Jul 15 18:11:15 weihong-pc polkitd(authority=local): Registered Authentication Agent for unix-session:c2 (system bus name :1.39 [/usr/lib/policykit-1-gnome/polkit-gnome-authentication-agent-1], object path /org/gnome/PolicyKit1/AuthenticationAgent, locale en_US.UTF-8) Jul 15 18:11:14 weihong-pc gnome-keyring-daemon[1622]: message repeated 2 times: [ couldn't set environment variable in session: The name org.gnome.SessionManager was not provided by any .service files] Jul 15 18:11:51 weihong-pc gnome-keyring-daemon[1622]: keyring alias directory: /home/weihong/.gnome2/keyrings After the upgrade, the log looks like: Jul 18 18:11:55 weihong-pc systemd-logind[1176]: New seat seat0. Jul 18 18:11:55 weihong-pc systemd-logind[1176]: Watching system buttons on /dev/input/event1 (Power Button) Jul 18 18:11:55 weihong-pc systemd-logind[1176]: Watching system buttons on /dev/input/event4 (Video Bus) Jul 18 18:11:55 weihong-pc systemd-logind[1176]: Watching system buttons on /dev/input/event0 (Power Button) Jul 18 18:11:58 weihong-pc lightdm: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory Jul 18 18:11:58 weihong-pc lightdm: PAM adding faulty module: pam_kwallet.so Jul 18 18:11:58 weihong-pc lightdm: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0) Jul 18 18:11:58 weihong-pc systemd-logind[1176]: New session c1 of user lightdm. Jul 18 18:11:58 weihong-pc systemd-logind[1176]: Linked /tmp/.X11-unix/X0 to /run/user/104/X11-display. Jul 18 18:11:58 weihong-pc lightdm: pam_ck_connector(lightdm-greeter:session): nox11 mode, ignoring PAM_TTY :0 Jul 18 18:12:03 weihong-pc lightdm: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory Jul 18 18:12:03 weihong-pc lightdm: PAM adding faulty module: pam_kwallet.so Jul 18 18:12:03 weihong-pc lightdm: pam_succeed_if(lightdm:auth): requirement "user ingroup nopasswdlogin" not met by user "weihong" Jul 18 18:12:06 weihong-pc dbus[1061]: [system] Rejected send message, 7 matched rules; type="method_return", sender=":1.22" (uid=0 pid=1338 comm="/usr/sbin/dnsmasq --no-resolv --keep-in-foreground") interface="(unset)" member="(unset)" error name="(unset)" requested_reply="0" destination=":1.11" (uid=0 pid=1239 comm="NetworkManager ") Jul 18 18:12:10 weihong-pc lightdm: pam_unix(lightdm-greeter:session): session closed for user lightdm Jul 18 18:12:10 weihong-pc lightdm: pam_unix(lightdm:session): session opened for user weihong by (uid=0) Jul 18 18:12:10 weihong-pc systemd-logind[1176]: New session c2 of user weihong. Jul 18 18:12:10 weihong-pc systemd-logind[1176]: Linked /tmp/.X11-unix/X0 to /run/user/1000/X11-display. Jul 18 18:12:10 weihong-pc lightdm: pam_ck_connector(lightdm:session): nox11 mode, ignoring PAM_TTY :0 Jul 18 18:13:22 weihong-pc systemd-logind[1176]: Failed to issue method call: Unknown unit: autovt@tty6.service Jul 18 18:13:40 weihong-pc login[894]: pam_unix(login:session): session opened for user weihong by LOGIN(uid=0) Jul 18 18:13:40 weihong-pc systemd-logind[1176]: New session c3 of user weihong. Jul 18 18:13:46 weihong-pc sudo: weihong : TTY=tty2 ; PWD=/home/weihong ; USER=root ; COMMAND=/sbin/reboot Jul 18 18:13:46 weihong-pc sudo: pam_unix(sudo:session): session opened for user root by weihong(uid=0) Jul 18 18:13:46 weihong-pc sudo: pam_unix(sudo:session): session closed for user root It seems this problem have a correlation with systemd-logind, gnome- keyring-daemon and polkitd. I hope these info do helps to this problem. -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1283826 Title: lightdm hangs after updates Status in GDM: The Gnome Display Manager: New Status in Light Display Manager: New Status in “lightdm” package in Ubuntu: Confirmed Bug description: I've updated today my Trusy Thar installation. I can't login to Unity, with my account, or a guest account. Lightdm hangs after password input, or after I click on the Guest account. Also, I used to auto-login. Now it greets me with the screen where I must input my password. After inputing it, lightdm hangs and I can't login. ProblemType: Bug DistroRelease: Ubuntu 14.04 Package: lightdm 1.9.8-0ubuntu1 ProcVersionSignature: Ubuntu 3.13.0-12.32-generic 3.13.4 Uname: Linux 3.13.0-12-generic x86_64 NonfreeKernelModules: nvidia ApportVersion: 2.13.2-0ubuntu5 Architecture: amd64 Date: Sun Feb 23 23:16:24 2014 InstallationDate: Installed on 2014-01-25 (29 days ago) InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Alpha amd64+mac (20140115) LightdmConfig: [SeatDefaults] autologin-guest=false autologin-user=cristi autologin-user-timeout=0 autologin-session=lightdm-autologin SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/gdm/+bug/1283826/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : desktop-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp