> The FreeBSD-AMD64 bot exhibits sporadic hanging in unspecific places.

You can try a shorter regrtest timeout, edit Lib/test/regrtest.py near:

    if hasattr(faulthandler, 'dump_tracebacks_later'):
        timeout = 60*60

(or use --timeout option of the regrtest.py program)

If you have an access to a terminal (using ssh), you can also set a signal to dump the traceback: edit regrtest.py to add "import signal; faulthandler.register(signal.SIGUSR1, all_threads=True)" after "faulthandler.enable()". Then use "kill -USR1 pid" to dump the traceback.

Or the problem is an unlimited loop while dumping the traceback because of a timeout :-D In this case, disable the timeout using --timeout=0 option of regrtest.py.