diff --git a/Lib/asyncio/sslproto.py b/Lib/asyncio/sslproto.py
@@ -551,8 +551,11 @@ def _get_extra_info(self, name, default=None):
    def _start_shutdown(self):
        if self._in_shutdown:
            return
-        self._in_shutdown = True
-        self._write_appdata(b'')

    def _write_appdata(self, data):
        self._write_backlog.append((data, 0))

diff --git a/Lib/test/test_asyncio/test_sslproto.py b/Lib/test/test_asyncio/test_sslproto.py
@@ -42,6 +42,7 @@ def mock_handshake(callback):
            sslpipe.do_handshake.side_effect = mock_handshake
        with mock.patch('asyncio.sslproto._SSLPipe', return_value=sslpipe):
            ssl_proto.connection_made(transport)

    def test_cancel_handshake(self):
        # Python issue #23197: cancelling a handshake must not raise an
@@ -95,6 +96,20 @@ def test_connection_lost(self):
        test_utils.run_briefly(self.loop)
        self.assertIsInstance(waiter.exception(), ConnectionAbortedError)

    def test_get_extra_info_on_closed_connection(self):
        waiter = asyncio.Future(loop=self.loop)
        ssl_proto = self.ssl_protocol(waiter)

diff --git a/Misc/NEWS b/Misc/NEWS
@@ -49,6 +49,9 @@ Core and Builtins
Library
-------

- bpo-27585: Fix waiter cancellation in asyncio.Lock.
  Patch by Mathieu Sornay.
-Original file line number
+Diff line change
@@ Expand Up / @@ -49,6 +49,9 @@ Core and Builtins @@
     Library
     -------
     - bpo-27585: Fix waiter cancellation in asyncio.Lock.
       Patch by Mathieu Sornay.