Comment 1 for bug 1310919

Another data point...

This problem also goes away with a world readable system keytab (/etc/krb5.keytab). So it isn't just the pam_winbind 'krb5_ccache_type=FILE' setting.

I'll do some more testing to find out whether or not changing the 'kerberos method = secrets and keytab' setting in smb.conf has any affect.

These keytab related areas have been ripe for winbind regressions in the past for us :)