Event loop is running error on starting jupyter notebook

Question

For some odd reason, after last night my jupyter kernel wouldn't start so I went ahead and removed it and pip3 installed it and now everytime I run jupyter notebook Im getting the following long stack trace in the termninal

[I 14:59:43.566 NotebookApp] Writing notebook server cookie secret to /run/user/1000/jupyter/notebook_cookie_secret
[I 14:59:43.885 NotebookApp] Serving notebooks from local directory: /home/dmitri/machine_learning/airbusShipDetection
[I 14:59:43.885 NotebookApp] The Jupyter Notebook is running at:
[I 14:59:43.885 NotebookApp] http://localhost:8888/?token=b98d3bd1ec284b81559e0a865c14d6a0932e0725a99d811d
[I 14:59:43.885 NotebookApp] Use Control-C to stop this server and shut down all kernels (twice to skip confirmation).
[C 14:59:43.885 NotebookApp] 

    Copy/paste this URL into your browser when you connect for the first time,
    to login with a token:
        http://localhost:8888/?token=b98d3bd1ec284b81559e0a865c14d6a0932e0725a99d811d
[I 14:59:44.624 NotebookApp] Accepting one-time-token-authenticated connection from 127.0.0.1
[I 14:59:48.412 NotebookApp] Kernel started: 15342e49-8fc3-402c-9964-eb8f4e2324c5
Traceback (most recent call last):
  File "/usr/lib/python3.5/runpy.py", line 184, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/lib/python3.5/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel_launcher.py", line 16, in <module>
    app.launch_new_instance()
  File "/home/dmitri/.local/lib/python3.5/site-packages/traitlets/config/application.py", line 658, in launch_instance
    app.start()
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelapp.py", line 477, in start
    ioloop.IOLoop.instance().start()
  File "/usr/local/lib/python3.5/dist-packages/tornado/platform/asyncio.py", line 132, in start
    self.asyncio_loop.run_forever()
  File "/usr/lib/python3.5/asyncio/base_events.py", line 340, in run_forever
    raise RuntimeError('Event loop is running.')
RuntimeError: Event loop is running.
ERROR:tornado.general:Uncaught exception in ZMQStream callback
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/zmq/eventloop/zmqstream.py", line 432, in _run_callback
    callback(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/tornado/stack_context.py", line 300, in null_wrapper
    return fn(*args, **kwargs)
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelbase.py", line 283, in dispatcher
    return self.dispatch_shell(stream, msg)
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelbase.py", line 233, in dispatch_shell
    self.pre_handler_hook()
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelbase.py", line 248, in pre_handler_hook
    self.saved_sigint_handler = signal(SIGINT, default_int_handler)
  File "/usr/lib/python3.5/signal.py", line 47, in signal
    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
ValueError: signal only works in main thread
ERROR:tornado.general:Uncaught exception in zmqstream callback
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/zmq/eventloop/zmqstream.py", line 450, in _handle_events
    self._handle_recv()
  File "/usr/local/lib/python3.5/dist-packages/zmq/eventloop/zmqstream.py", line 480, in _handle_recv
    self._run_callback(callback, msg)
  File "/usr/local/lib/python3.5/dist-packages/zmq/eventloop/zmqstream.py", line 432, in _run_callback
    callback(*args, **kwargs)
  File "/usr/local/lib/python3.5/dist-packages/tornado/stack_context.py", line 300, in null_wrapper
    return fn(*args, **kwargs)
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelbase.py", line 283, in dispatcher
    return self.dispatch_shell(stream, msg)
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelbase.py", line 233, in dispatch_shell
    self.pre_handler_hook()
  File "/home/dmitri/.local/lib/python3.5/site-packages/ipykernel/kernelbase.py", line 248, in pre_handler_hook
    self.saved_sigint_handler = signal(SIGINT, default_int_handler)
  File "/usr/lib/python3.5/signal.py", line 47, in signal
    handler = _signal.signal(_enum_to_int(signalnum), _enum_to_int(handler))
ValueError: signal only works in main thread
[W 15:00:48.619 NotebookApp] Timeout waiting for kernel_info reply from 15342e49-8fc3-402c-9964-eb8f4e2324c5
[I 15:01:49.148 NotebookApp] Saving file at /u-net-model-with-submission.ipynb
^C[I 15:02:46.820 NotebookApp] interrupted
Serving notebooks from local directory: /home/dmitri/machine_learning/airbusShipDetection
1 active kernel
The Jupyter Notebook is running at:

The notebook itself says the kernel is loading, but it never finishes loading.

Answer 1

I had the same problem after upgrading notebook.

Upgrading tornado and ipykernel fixed it for me.

Answer 2

If you use the following commands in your terminal, it should work:

pip install tornado==5.1.1

and

pip install -U ipykernel

After rolling back "tornado" and updating "ipykernel" everything worked.