RFC: Too many race conditions.

[Florian Weimer]

> No. Dave already described this a few times. If close() cannot execute
> until accept() completes, then close() cannot be used to cause the
> accept() to complete prematurely. Therefore, blocking accept() loop
> lives forever, until the next accept() completes.
>
> User space *cannot* solve this problem.

Userspace can interrupt the relevant threads before calling close().
This needs quite a bit of synchronization, though.