I just tried running 'dpkg --configure -a' from a text VT whilst gdm was still running, and it was fine. So it seems to be something about the postinst running inside a gnome-terminal that breaks things.
-- package gdm 2.28.0-0ubuntu8 failed to install/upgrade: subprocess installed post-installation script returned error exit status 1 https://bugs.launchpad.net/bugs/438561 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