[dgrunwald]

Your "third party libs" includes system libraries like libdl.

We had a Python process using both threads (for stuff like background downloads, where the GIL doesn't hurt) and multiprocessing (for CPU-intensive work), and found that on Linux, the child process sometimes deadlocks in libdl (which Python uses to import extension modules).

The fix was to use `multiprocessing.set_start_method('spawn')` so that Python doesn't use fork().

[kazinator]

libdl is a component of glibc; that needs to be debugged.