Seeing this as well when running the cpython test suite in docker:

```
$ ./python -m test.test_asyncio

...

[18 similar traces omitted]
======================================================================
ERROR: test_sock_sendfile_zero_size (test.test_asyncio.test_unix_events.SelectorEventLoopUnixSockSendfileTests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/code/Lib/test/test_asyncio/test_unix_events.py", line 559, in test_sock_sendfile_zero_size
    sock, proto = self.prepare()
  File "/code/Lib/test/test_asyncio/test_unix_events.py", line 483, in prepare
    lambda: proto, support.HOST, port))
  File "/code/Lib/test/test_asyncio/test_unix_events.py", line 476, in run_loop
    return self.loop.run_until_complete(coro)
  File "/code/Lib/asyncio/base_events.py", line 566, in run_until_complete
    return future.result()
  File "/code/Lib/asyncio/base_events.py", line 1346, in create_server
    % (sa, err.strerror.lower())) from None
OSError: [Errno 99] error while attempting to bind on address ('::1', 39527, 0, 0): cannot assign requested address

----------------------------------------------------------------------

```


I'm going to try and write a patch to skip these tests (there's already a helper)