If the following conditions are met:

- /var/gdm/.gdmfifo is left over across a reboot (say, the box crashes while gdm
is running, or you're testing suspend&resume from the text console, and suspend
works but resume doesn't :-/

- early gdm is not enabled

- any init.d script fails to start while booting up

then boot will hang within failure(), because it attempts to write to a pipe and
nobody is listening.

Ideally, we'd clean up /var/gdm/.gdmfifo before running any script that might
call failure(), but there are scripts that do so before root or /var are made
read-write, e.g., the very commands that remount / read-write and that mount
other filesystems.  The latter may actual fail without any undesirable
consequences for filesystems marked to be mounted by default with fs_passno ==
0, such that boot doesn't stop if the removable media containing them happen to
not be present.  (guess what happened to me during my last trip, to which I
didn't take my external hard drive along with my notebook :-)

I suppose it wouldn't be such a bad idea to move /var/gdm/.gdmfifo to some
directory that is rw right from the beginning such as /dev (assuming udev) or
somesuch, like notting suggested for another lvm-related problem.