HEADS UP - DEVFS ON MASTER

[YONETANI Tomokazu]

On Mon, Aug 03, 2009 at 10:16:25PM -0700, Matthew Dillon wrote:
>     * If you run a new kernel with an old world (without devfs) you will
>       not be able to login as root, but you will still be able to login
>       as a user and su, and you should still be able to boot single-user.
> 
>       In otherwords, things will be messed up but in a fixable way, until
>       both the world and the kernel are in sync.

If you run a new kernel with an old world, you can't login to the
machine via ssh after the reboot, even as a non-root user, because tty
allocation fails.  You can still slogin to the machine without allocating
a tty (that is, ssh -T the.machine), but then you can't su to root.
I eventually worked around this by feeding the password to sudo via stdin,
then running `make installworld', followed by `make upgrade'.

IOW: don't be too brave when you're going through a big change :)