faulthandler: dump all threads by default * Set the default value of all_threads arguments to True * Py_FatalError() dumps all threads, instead of only the current thread Dump only the current thread is not reliable. In some cases, Python is unable to retrieve the state of the current thread and so is unable to dump the traceback. faulthandler keeps a reference to the interpreter and so is always able to dump the traceback of all threads.