Hi,
I've noticed the following behaviour on my Linux 2.6.10 box (grsecurity-2.1.1, development version 01/14/2005).
After running "gradm -a role" or "gradm -D" in a xterm (e.g. /dev/pts/0) the filesystem /dev/pts is busy when I'm shutting down the system (/dev/pts is empty, though). Due to this, the root filesystem cannot be unmounted as well.
The problem does not occur, if gradm is used on a virtual console (/dev/tty1 for example).
-vs