gunicorn worker crash at winch signal when using eventlet as worker class
<p>So I have a flask app that needs to run with <code>gunicorn --worker-class eventlet</code>.</p>

<p>But when I start the app like this in an iterm2 pane, the worker crashes when I resize the pane (send winch signal):</p>

<pre><code>[2016-11-07 11:03:38 +0800] [57382] [INFO] Handling signal: winch
[2016-11-07 11:03:38 +0800] [57385] [ERROR] Exception in worker process
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/gunicorn/arbiter.py", line 557, in spawn_worker
    worker.init_process()
  File "/usr/local/lib/python2.7/site-packages/gunicorn/workers/geventlet.py", line 96, in init_process
    super(EventletWorker, self).init_process()
  File "/usr/local/lib/python2.7/site-packages/gunicorn/workers/base.py", line 132, in init_process
    self.run()
  File "/usr/local/lib/python2.7/site-packages/gunicorn/workers/geventlet.py", line 125, in run
    eventlet.sleep(1.0)
  File "/usr/local/lib/python2.7/site-packages/eventlet/greenthread.py", line 34, in sleep
    hub.switch()
  File "/usr/local/lib/python2.7/site-packages/eventlet/hubs/hub.py", line 294, in switch
    return self.greenlet.switch()
  File "/usr/local/lib/python2.7/site-packages/eventlet/hubs/hub.py", line 346, in run
    self.wait(sleep_time)
  File "/usr/local/lib/python2.7/site-packages/eventlet/hubs/kqueue.py", line 100, in wait
    result = self._control([], self.MAX_EVENTS, seconds)
  File "/usr/local/lib/python2.7/site-packages/eventlet/hubs/kqueue.py", line 43, in _control
    return self.kqueue.control(events, max_events, timeout)
OSError: [Errno 4] Interrupted system call
[2016-11-07 11:03:38 +0800] [57385] [INFO] Worker exiting (pid: 57385)
Exception TypeError: TypeError("'NoneType' object is not callable",) in &lt;bound method Client.__del__ of &lt;etcd.client.Client object at 0x10290a5d0&gt;&gt; ignored
[2016-11-07 11:03:38 +0800] [57394] [INFO] Booting worker with pid: 57394
</code></pre>

<p>FYI:
* I also use grpc in my code.
* This doesn't occur on my remote centos 7 server, only my mac</p>