Long story short

We have small aiohttp-based running on many customers servers. All errors from these servers are reported to Sentry. There are many errors whitch looks like aiohttp bugs, here's details:

Fatal error on SSL transport
protocol: <asyncio.sslproto.SSLProtocol object at 0x7f3388134400>
transport: <_SelectorSocketTransport closing fd=30 read=idle write=<idle, bufsize=0>>

AttributeError: 'NoneType' object has no attribute 'feed_appdata'
  File "asyncio/sslproto.py", line 637, in _process_write_backlog
    ssldata, offset = self._sslpipe.feed_appdata(data, offset)

Steps to reproduce

Unfortunately, we can not reproduce this issue on our environment and do not have access to affected servers.

Your environment

aiohttp server 2.3.2
Centos 6/7

Please advice