Some requests are received and processed twice?

[derklaro]

I'm running on the latest "release" of io_uring (0.0.13.Final). I recently noticed build failures on GitHub Actions which seem the be caused
by io_uring. Removing io_uring and only testing against epoll/kqueue/nio works perfectly fine.

I had originally two issues, one of them I was able to solve myself. However, that might be interesting as well: I have some code which did a websocket handshake, I executed it and called syncUninterruptedly which began to fail as well. Seems like I need to execute/handle that async, wich worked seemlessly a few days ago.

On the other hand I am testing if sent http requests are having the same request method when receiving. In a nutshell this code looks like this:

        Assertions.assertEquals(SUPPORTED_METHODS.get(handledTypes.getAndIncrement()), context.request().method());
        // send ok http response

And I send the request with an HttpUrlConnection:

    for (String supportedMethod : SUPPORTED_METHODS) {
      HttpUrlConnection connection = construct_here;
      connection.setRequestMethod(supportedMethod)
      connection.connect();

      Assertions.assertEquals(200, connection.getResponseCode());
    }

But I receive some requests twice:

    SENDING WITH GET
    GOT GET /// 0 /// IOUringEventLoopGroup-7-1
    SENDING WITH POST
    GOT POST /// 1 /// IOUringEventLoopGroup-7-2
    SENDING WITH HEAD
    GOT HEAD /// 2 /// IOUringEventLoopGroup-7-3
    SENDING WITH OPTIONS
    GOT OPTIONS /// 3 /// IOUringEventLoopGroup-7-3
    GOT OPTIONS /// 4 /// IOUringEventLoopGroup-7-4

or

    SENDING WITH GET
    GOT GET /// 0 /// IOUringEventLoopGroup-7-1
    SENDING WITH POST
    GOT POST /// 1 /// IOUringEventLoopGroup-7-2
    SENDING WITH HEAD
    GOT HEAD /// 2 /// IOUringEventLoopGroup-7-2
    GOT HEAD /// 3 /// IOUringEventLoopGroup-7-3

I'm pretty sure that the request is not sent twice as that test works fine with epoll and nio. I wasn't yet able to validate this, but there was a recent kernel update which changed stuff related to io_uring, maybe it's a good start to check if it works fine on older kernel versions? (https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=42a7b4ed45e7667836fae4fb0e1ac6340588b1b0)