NetBSD-5.1 kernel crash with msdos filesystem

[Sad Clouds <cryintothebluesky%googlemail.com@localhost>]

This is happening on amd64 architecture. Mount msdos filesystem and
then try to create directory on that filesystem with mkdir. You
immediately get kernel crash.

At the moment I don't have a backtrace (USB keyboard does not respond
in kernel debugger). I vaguely remember seeing this before, but I'm not
too sure on the details.

Is anyone else seeing this? This seems to happen only on 64-bit
architectures, like amd64. Any ideas?