I get the unable to connect message about 10 secs after boot but no further lightdm messages, and no obvious ill effect, so perhaps it is unrelated to the PAM messages. In fact the only lightdm messages I see are:
$ grep -i lightdm /var/log/syslog Apr 6 09:57:14 tigger kernel: [ 10.835217] audit: type=1400 audit(1428310634.471:2): apparmor="STATUS" operation="profile_load" profile="unconfined" name="/usr/lib/lightdm/lightdm-guest-session" pid=512 comm="apparmor_parser" Apr 6 09:57:21 tigger lightdm[1449]: initctl: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused syslog contained the complete boot sequence, and more. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1414420 Title: initctl: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused Status in Light Display Manager: Confirmed Status in lightdm package in Ubuntu: Triaged Bug description: That vivid system booted with systemd (systemd-sysv installed) have logged to journalctl: lightdm[1195]: initctl: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused lightdm[1220]: PAM unable to dlopen(pam_kwallet.so): /lib/security/pam_kwallet.so: cannot open shared object file: No such file or directory lightdm[1220]: PAM adding faulty module: pam_kwallet.so lightdm[1220]: pam_unix(lightdm-greeter:session): session opened for user lightdm by (uid=0) ProblemType: Bug DistroRelease: Ubuntu 15.04 Package: lightdm 1.13.1-0ubuntu2 ProcVersionSignature: Ubuntu 3.19.0-2.2-generic 3.19.0-rc4 Uname: Linux 3.19.0-2-generic i686 NonfreeKernelModules: nvidia ApportVersion: 2.15.1-0ubuntu2 Architecture: i386 CurrentDesktop: GNOME Date: Sun Jan 25 11:35:37 2015 SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) To manage notifications about this bug go to: https://bugs.launchpad.net/lightdm/+bug/1414420/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp