pykafka deadlock on nosetests' integration tests - python-3.6

Question

we are having issues with pykafka 2.7.0 on python3.6. There are some integration tests, and for some reason a deadlock is formed on topics we produce to. The nosetests refuses to finish after all tests finished. This does not happen when we run the same tests on python2.7, and we have used pykafka 2.8.0 on python3.6 with no help.
Only way it got fixed is a temp fix of stopping/deleting the producer right after a message is produced to the topic(as you can see in last 2 line of code), which is costing a lot of time just to stop the producer.
def publish(self, topic, message):
topic = topic.lower()
self._log.info('publish top topic ' + topic)
if topic not in self.producer_map:
k_topic = self.__messenger.topics[topic.encode()]
self._log.info(k_topic)
new_producer = k_topic.get_producer()
self.producer_map[topic] = new_producer
self.producer_map[topic].produce(message)
# The fix
self.producer_map[topic].stop()
del self.producer_map[topic]
If the last 2 lines were not there, I see in gdb that the process in stuck right after garbage collecting, and trying to stop the producer. Then it hangs at _wait_for_tstate_lock. It is preventing our CI in Jenkins from finishing, and would like to know why it deadlocks on garbage collection but not when called in code.
#9 Frame 0x7f4824fe7958, for file /usr/lib64/python3.6/threading.py, line 1072, in _wait_for_tstate_lock (self=<Thread(_target=<function at remote 0x7f4824ef4ae8>, _name='3: pykafka.OwnedBroker.queue_reader for broker 0', _args=(), _kwargs={}, _daemonic=True, _ident=139948465846016, _tstate_lock=<_thread.lock at remote 0x7f4824de78a0>, _started=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de7670>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de7670>, release=<built-in method release of _thread.lock object at remote 0x7f4824de7670>, _waiters=<collections.deque at remote 0x7f4824ddc2b8>) at remote 0x7f4824de3128>, _flag=True) at remote 0x7f4824de31d0>, _is_stopped=False, _initialized=True, _stderr=<redacted>, <redacted>, <_io.TextIOWrapper at remote 0x7f48549b1708>)) at remote 0x7f48275474a8>)) at remote 0x7f4827547518>)) at remote 0x7f48275476d8>) at remote 0x7f4824de3160>, block=True, timeout=-1, lock=<_thread.lock at remote 0x7f4824de78a0>)
elif lock.acquire(block, timeout):
#13 Frame 0x7f4824e045a0, for file /usr/lib64/python3.6/threading.py, line 1056, in join (self=<Thread(_target=<function at remote 0x7f4824ef4ae8>, _name='3: pykafka.OwnedBroker.queue_reader for broker 0', _args=(), _kwargs={}, _daemonic=True, _ident=139948465846016, _tstate_lock=<_thread.lock at remote 0x7f4824de78a0>, _started=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de7670>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de76---Type <return> to continue, or q <return> to quit---
70>, release=<built-in method release of _thread.lock object at remote 0x7f4824de7670>, _waiters=<collections.deque at remote 0x7f4824ddc2b8>) at remote 0x7f4824de3128>, _flag=True) at remote 0x7f4824de31d0>, _is_stopped=False, _initialized=True, _stderr=<redacted>, <redacted>, <redacted>, <redacted>)) at remote 0x7f4827547518>)) at remote 0x7f48275476d8>) at remote 0x7f4824de3160>, timeout=None)
self._wait_for_tstate_lock()
#17 (frame information optimized out)
#21 Frame 0x7f484d8bee08, for file /usr/local/lib/python3.6/site-packages/pykafka/producer.py, line 235, in __del__ (self=<Producer(_cluster=<Cluster(_seed_hosts='<redacted>:9092', _socket_timeout_ms=30000, _offsets_channel_socket_timeout_ms=10000, _handler=<ThreadingHandler at remote 0x7f4824e81da0>, _brokers={0: <Broker(_connection=<BrokerConnection(_buff=<bytearray at remote 0x7f4824fdb228>, host=b'<redacted>', port=9092, _handler=<...>, _socket=<socket at remote 0x7f4824dff048>, source_host='', source_port=0, _wrap_socket=<function at remote 0x7f4824dfba60>) at remote 0x7f4824fd5898>, _offsets_channel_connection=None, _id=0, _host=b'<redacted>', _port=9092, _source_host='', _source_port=0, _ssl_config=None, _handler=<...>, _req_handler=<RequestHandler(handler=<...>, shared=<Shared at remote 0x7f4824dd0048>, t=<Thread(_target=<function at remote 0x7f4824dfbae8>, _name="1: pykafka.RequestHandler.worker for b'<redacted>':9092", _args=(), _kwargs={}, _daemonic=True, _ident=139948381951744, _tstate_lock=<_thread.lock at remote 0x7f4824de7120>, _started=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de71e8>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de71e8>, release=<built-in method release of _thread.lock object at remote 0x7f4824de71e8>, _waiters=<collections.deque at remote 0x7f4824e079a0>) at remote 0x7f4835420198>, _flag=True) at remote 0x7f4835424358>, _is_stopped=False, _initialized=True, _stderr=<redacted>, <redacted>, <redacted>, <_io.TextIOWrapper at remote 0x7f48549b1708>)) at remote 0x7f48275474a8>)) at remote 0x7f4827547518>)) at remote 0x7f48275476d8>) at remote 0x7f4835424940>) at remote 0x7f4824f62438>, _offsets_channel_req_handler=None, _socket_timeout_ms=30000, _offsets_channel_socket_timeout_ms=10000, _buffer_size=1048576, _req_handlers={}, _broker_version='0.9.0', _api_versions={0: <ApiVersionsSpec at remote 0x7f4824e88408>, 1: <ApiVersionsSpec at remote 0x7f4824e88458>, 2: <ApiVersionsSpec at remote 0x7f4824e884a8>, 3: <ApiVersionsSpec at remote 0x7f4824e884f8>, 4: <ApiVersionsSpec at remote 0x7f4824e88548>, 5: <ApiVersionsSpec at remote 0x7f4824e88598>, 6: <ApiVersionsSpec at remote 0x7f4824e885e8>, 7: <ApiVersionsSpec at remote 0x7f4824e88638>, 8: <ApiVersionsSpec at remote 0x7f4824e88688>, 9: <ApiVersionsSpec at remote 0x7f4824e886d8>, 10: <ApiVersionsSpec at remote 0x7f4824e88728>, 11: <ApiVersionsSpec at remote 0x7f4824e88778>, 12: <ApiVersionsSpec at remote 0x7f4824e887c8>, 13: <ApiVersionsSpec at remote 0x7f4824e88818>, 14: <ApiVersionsSpec at remote 0x7f4824e88868>, 15: <ApiVersionsSpec at remote 0x7f4824e888b8>, 16: <ApiVersionsSpec at remote 0x7f4824e88908>}) at remote 0x7f482500f4e0>}, _topics=<TopicDict(_cluster=<weakref at remote 0x7f4824f9c4f8>, _exclude_internal_topics=True) at remote 0x7f4824fcd888>, _source_address='', _source_host='', _source_port=0, _ssl_config=None, _zookeeper_connect=None, _max_connection_retries=3, _max_connection_retries_offset_mgr=8, _broker_version='0.9.0', _api_versions={...}, controller_broker=None) at remote 0x7f4824ed8198>, _protocol_version=0, _topic=<Topic(_name=b'<redacted>', _cluster=<...>, _partitions={0: <Partition(_id=0, _leader=<...>, _replicas=[<...>], _isr=[<...>], _topic=<weakref at remote 0x7f4824e0cdb8>) at remote 0x7f48353ffbe0>}) at remote 0x7f4824deedd8>, _partitioner=<RandomPartitioner(idx=0) at remote 0x7f48526baba8>, _compression=0, _max_retries=3, _retry_backoff_ms=100, _required_acks=1, _ack_timeout_ms=10000, _max_queued_messages=100000, _min_queued_messages=70000, _linger_ms=5000, _queue_empty_timeout_ms=0, _block_on_queue_full=True, _max_request_size=1000012, _synchronous=False, _worker_exception=None, _owned_brokers={0: <OwnedBroker(producer=<weakproxy at remote 0x7f4824e0ce08>, broker=<...>, lock=<_thread.RLock at remote 0x7f4824fd8420>, flush_ready=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de7698>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de7698>, release=<built-in method release of _thread.lock object at remote 0x7f4824de7698>, _waiters=<collections.deque at remote 0x7f4824ddc118>) at remote 0x7f4824de3320>, _flag=False) at remote 0x7f4824de33c8>, has_message=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de7710>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de7710>, release=<built-in method release of _thread.lock object at remote 0x7f4824de7710>, _waiters=<collections.deque at remote 0x7f4824ddc0b0>) at remote 0x7f4824de3240>, _flag=True) at remote 0x7f4824de3390>, slot_available=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de7788>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de7788>, release=<built-in method release of _thread.lock object at remote 0x7f4824de7788>, _waiters=<collections.deque at remote 0x7f4824ddc180>) at remote 0x7f4824de3208>, _flag=True) at remote 0x7f4824de3278>, queue=<collections.deque at remote 0x7f4824ddc1e8>, messages_pending=2, running=False, _auto_start=True, _queue_reader_worker=<Thread(_target=<function at remote 0x7f4824ef4ae8>, _name='3: pykafka.OwnedBroker.queue_reader for broker 0', _args=(...), _kwargs={}, _daemonic=True, _ident=139948465846016, _tstate_lock=<_thread.lock at remote 0x7f4824de78a0>, _started=<Event(_cond=<Condition(_lock=<_thread.lock at remote 0x7f4824de7670>, acquire=<built-in method acquire of _thread.lock object at remote 0x7f4824de7670>, release=<built-in method release of _thread.lock object at remote 0x7f4824de7670>, _waiters=<collections.deque at remote 0x7f4824ddc2b8>) at remote 0x7f4824de3128>, _flag=True) at remote 0x7f4824de31d0>, _is_stopped=False, _initialized=True, _stderr=<...>) at remote 0x7f4824de3160>) at remote 0x7f4824e81cc0>}, _delivery_reports=<_DeliveryReportNone(queue=None) at remote 0x7f4824e814a8>, _pending_timeout_ms=5000, _auto_start=True, _serializer=None, _running=True, _update_lock=<_thread.lock at remote 0x7f4824de7620>) at remote 0x7f4824fdb208>)
self.stop()
#30 Garbage-collecting