Had two Debian stable (as of 2009-05-28) servers suddenly broken, when /dev/null became unwritable. It appeared that when I restart udev it sometimes (randomly) changes /dev/null permissions sometimes making it unwritable. Server configuration is pretty standard and no udev rules are changed. Does anyone know what kind of a bug this can be?
I've had this many times, and often it was because the static files were bad.
You might want to try:
To see what the boot-time permissions will be, and:
To set them
Also, from the Debian wiki on udev, you may be able to look at / fix the init scripts for it.
From a related discussion on Ubuntu, it appears it's been fixed at least there.
Not sure if those'll help/fix you problem, but maybe they're in the right direction :)