ChannelUpstreamHandler.handleUpstream bug - InterestOps changed

[Kr0e]

Hi, 

I think I found a bug:

The Doc of the ChannelUpstreamHandler says:

 * {@link #handleUpstream(ChannelHandlerContext, ChannelEvent)
handleUpstream}
 * will be invoked sequentially by the same thread (i.e. an I/O thread) and
 * therefore a handler does not need to worry about being invoked with a new
 * upstream event before the previous upstream event is finished.

But I've found that this does not apply:

    @Override
    public void channelInterestChanged(ChannelHandlerContext ctx,
	    ChannelStateEvent e) throws Exception {

	System.out.println("INTER : " + Thread.currentThread());

	// Super
	super.channelInterestChanged(ctx, e);
    }
    @Override
    public void messageReceived(ChannelHandlerContext ctx, MessageEvent e)
	    throws Exception {

	System.out.println("RECV : " + Thread.currentThread());
    }

RECV : Thread[New I/O server worker #1-1,5,main]
INTER : Thread[New I/O client worker #1-1,5,main]
INTER : Thread[main,5,main]
RECV : Thread[New I/O server worker #1-1,5,main]
INTER : Thread[New I/O client worker #1-1,5,main]
INTER : Thread[main,5,main]
RECV : Thread[New I/O server worker #1-1,5,main]
INTER : Thread[New I/O client worker #1-1,5,main]
INTER : Thread[main,5,main]
RECV : Thread[New I/O server worker #1-1,5,main]
INTER : Thread[New I/O client worker #1-1,5,main]


As you can see the super method handleUpstream is not always called by the
same thread. This causes a race condition in our software.

In our software the client sends as fast as possible data to the server. If
the client channel is not writable the client waits until it is writable and
continues. The server receives the data. The server handles the data in an
extra thread pool. If the server receives data too fast it calls
channel.setReadable(false);. But when the server is able to process more
data and calls channel.setReadable(true); the method
channelInterestChanged(...) is called concurrently which causes a race
condition.

Is this intended ?

Regards,

Chris

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