I am finding when using the dask Profiler that I get errors like "AssertionError: can only join a child process" and this causes the IPython kernel to enter a state where it cannot be shut down from within Jupyter and needs to be killed manually. Example here: https://gist.github.com/alimanfoo/68f15f57c41db3df1652b54ff9c26a84