I had that exact error one day before the HD on my HP laptop dumped. I thought "oh, core dump. Happens all the time in Linux. I'll reboot and see what happens."
Wrong!
Turns out I was letting the laptop run and run and run without shutting it off. Put it in the bag, pull it out, have it sitting around for days without rebooting. My theory is that while running in the bag the thing generated tons of heat and literally burned up all by itself. You don't do that... do you?
Save your files now and go buy a new drive.