It's definitely not the CDROM here, the UL30VT hasn't got a optical drive at all. It seems to crop up in different ways, last time udevd went crazy it happened while downloading to an ordinarily mounted HD partition with a perfect ext3 filsystem on it. Just had to kill it before it started killing everything else. And the drive was correctly listed in /etc/fstab.

I'm not terribly interested in getting to the roots of this, as they seem to be multiple, and the basic architecture may have some flaws - I interpret some kernel dev discussions that way.
Basically, we only need the hotplug manager when things are plugged in and out, otherwise it can rest. Therefore, a safe and simple workaround may be to let it autostart, but stop the daemon when system is set up fine, and only start it when changes are made. And if udevd takes 1% or more of CPU in top's listing, it may be an indication of malfunctioning. Then, it may be safest to stop it (sudo /etc/init.d udev stop) and only restart it when needed.

A program like udevadm is surely useful for debugging, and for system administration when a lot of complex hotplugging is going on. But it should not be necessary to use when no hotplugging is going on at all!