note: a widespread remnant of this bug on ubuntu is this string in users' (mine included) Xorg.0.logs:
~$ cat /var/log/Xorg.0.log | grep SecurityPolicy error opening security policy file /etc/X11/xserver/SecurityPolicy this is a file from xserver-common, not included with Ubuntu / Deb Unstable. thanks -- [ia64] gdm: impossible to login / missing xserver-common package https://launchpad.net/bugs/40748 -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs