Can someone point me to the code or documentation about why some processes
won't be killed?

I understand that it is safer to not kill a process when it is in some
special use. But what if I don't care?

For example, I have a few processes that just won't die. And it has been
over a week.

Two are umounts in synclk. (Which happens to be unmounting /dev/fd0a,
which can't be used.)

And one shlight in mntwcnt2.

And unshlight in vfs_busy.

(Maybe PR 1247 is related?)

By the way, this is 1.6 i386.

I've been looking at kern/kern_sig.c.

Thanks,

   Jeremy C. Reed
   http://bsd.reedmedia.net/