Re: In-kernel process exit hooks?

[Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost>]

Another possibility would be to change filemon(4) to do fd_getfile
each it needs to use the file descriptor.  This makes it a little more
brittle (fails if you close the descriptor), but would sidestep the
problem.

Another possibility would be to use fd_getfile2/closef, which holds a
reference only on the file, instead of fd_getfile/fd_putfile, which
holds a reference on the file and on the descriptor.  Releasing the
reference to the file may not a problem, even though releasing the
reference to the descriptor is a problem as you found.