Robert Pierce added the comment:
It appears as if the problem is the sentinel FIFO opened by (for example)
multiprocessing.popen_fork.Popen._launch(). It registers a finalization class
to close the sentinel on garbage collection. Instead, it should be closed in
poll() or wait() when the
New submission from Robert Pierce :
multiprocessing.Process opens a FIFO to the child. This FIFO is not documented
the the Process class API and it's purpose is not clear from the documentation.
It is a minor documentation bug that the class creates non-transparent resource
utilization.
The
