After asking about this on a mailing list, Martin Pitt kindly informed me that ACL is indeed used in Ubuntu and thus the +-signs. The ACL is set by udev using the ruleset in /lib/udev/rules.d/70-acl.rules
The rationale to use ACL in Ubuntu is that with it the system can control that e.g. inserted USB-drives can be accessed by the user who's console is currently active in stead of any user who is logged in. I tried toggling consoles with Ctrl+Alt+F1-8, but it didn't help. Restarting udev just says: $ restart udev restart: Rejected send message, 1 matched rules; type="method_call", sender=":1.51" (uid=1000 pid=2038 comm="restart) interface="com.ubuntu.Upstart0_6.Job" member="Restart" error name="(unset)" requested_reply=0 destination="com.ubuntu.Upstart" (uid=0 pid=1 comm="/sbin/init")) udev logs, ConsoleKit logs etc. does not show anything suspicious. However in syslog I found lines like: Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Could not determine active console Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 4 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 5 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 7 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 9 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 11 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 13 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 15 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 3 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 28 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 48 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 6 activation: Invalid argument Mar 17 21:40:42 shuttle console-kit-daemon[874]: WARNING: Error waiting for native console 54 activation: Invalid argument Might they be related? Any tips on how to continue debugging this? -- [regression] Unable to shut down, login screen keeps coming up https://bugs.launchpad.net/bugs/537596 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs