I just had my Linux install go fubar on me. The reason?
I'd commented out the <dri> line in
my /etc/security/console.perms so that a game demo I just
installed would work.
Upon reboot, almost immediately I get an inexplicable error along the lines of "**CRITICAL** ... unknown [something] <dri>" and then my boot disk wasn't recognised. Nothing would seem to work when I was dumped to the prompt - it was like the disk just didn't exist.
This had me all panicky about superblocks going bad (and unreasonably cursing Windows as the cause). After looking into it using the rescue disk, the disk was just fine - I could mount it, edit stuff on it and it was just fine and dandy. So I edited the console.perms file, uncommented the <dri> line, and voila, the machine boots ok.
This is an hour of hand-wringing later, of course. Next time a demo
wants write permission to /dev/nvidiactl, I'll just chmod it
on the spot.
It turns out I'd only commented out the "class" specification which indicates what <dri> means in that file. I'd missed that much lower in the file that <dri> symbol is actually used in another statement. When that statement is attempted, <dri> is unknown and the whole thing goes barf-o. It's just a tad unfortunate that this results in none of my disk devices being created...