Comment 3 for bug 1195474

I'm seeing this on 3.8.0-19-generic at Amazon EC2 as well. It's very reproducible (happens every time), and it causes a bizarre (theoretically impossible) state for my sockets. I have a client and a server on separate machines, both running Ubuntu 13.04 on EC2, and shortly into a stress test, all traffic ceases. I can watch the output from netstat on the two machines, and there is no change in the sockets' queue lengths. The client's socket has zero bytes in both its send queue and its receive queue. The server's socket has zero bytes in its receive queue and a few hundred thousand bytes in its send queue. Theoretically this state should be impossible unless the client has reduced its receive window size to zero. (I don't know any reason why it would be doing that, so I'm ruling that out.) Given that there is available space in the client's receive queue and pending bytes in the server's send queue, bytes should be moving from the server to the client, but this is not happening. The entire test hangs at this point until eventually the connection times out (after several minutes).