Hello, cafe! I have the following code (paraphrased): ... forkIO spin ... spin = do (t, _) <- accept s -- (*) forkIO $ dealWith t -- (**) spin My problem is that I want to stop spin from another thread. The "obvious" solution would be to throw it an exception. However, that leaks a socket (t) if the exception arrives between (*) and (**). I could wrap the whole thing in block, but from looking at the source of Network.Socket it seems that accept itself is not exception safe; so no matter what I do, I can't use asynchronous exceptions to make spin exit. (Is this actually true? Should accept be fixed (along with a lot of other library functions)?) Another idea is to sClose s in another thread. This makes accept throw an IO exception, which breaks the loop. Yay! But it introduces another race condition: If a third thread creates a socket between sClose and accept, the underlying file descriptor of s may get reused, leading to silently wrong behavior because accept listens on the wrong socket now. My question is: How can I use accept in a loop so that I can safely stop it from another thread? Lukas