Today: Reiserfs craps out on fileserver trying to free previously
freed objects, and kupdated tries to deref a null pointer and oopses.
Userland stops, but instead of halting, kernel continues to run other
threads, including nfsd, which was apparently completely unaware
that anything was amiss.
Writing to a filesystem which has already given up for the day should
probably be considered harmful, I think.
Someone somewhere probably thinks that continuing to run after an oops
in kupdated is a feature.