FULL PRODUCT VERSION :
Both 1.7 and 1.8 JREs


ADDITIONAL OS VERSION INFORMATION :
Both Linux and Windows

A DESCRIPTION OF THE PROBLEM :
When we attempt to interrupt a thread sending data on a DatagramChannel, we sometimes encounter a deadlock between the thread doing the interrupt and the thread sending the data. We've determined that the locks in question are java.lang.Thread's blockerLock and sun.nio.ch.DatagramChannelImpl's stateLock.

I've included a test program which can reproduce it. ~40% of the time it happens on the first iteration, otherwise it could take some time.


REPRODUCIBILITY :
This bug can be reproduced occasionally.

---------- BEGIN SOURCE ----------
import java.io.IOException;
import java.net.InetSocketAddress;
import java.net.StandardSocketOptions;
import java.nio.ByteBuffer;
import java.nio.channels.DatagramChannel;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.ThreadLocalRandom;

import org.junit.Test;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class DeadlockTest
{
  private static final Logger LOG = LoggerFactory.getLogger(DeadlockTest.class);
  private DatagramChannel receiver;
  private InetSocketAddress target = new InetSocketAddress("localhost", 42421);
  private boolean running = true;

  private class Sender implements Runnable
  {
    private Thread thisThread = null;

    /**
     * @see java.lang.Runnable#run()
     */
    @Override
    public void run()
    {
      thisThread = Thread.currentThread();
      while (running)
      {
        try
        {
          DatagramChannel sender = DatagramChannel.open();
          sender.setOption(StandardSocketOptions.SO_REUSEADDR, true);
          sender.connect(target);

          LOG.info("Sending");
          sender.send(ByteBuffer.allocate(100).putInt(1), target);
          // Sooner or later you stop seeing this message
          LOG.info("Sent");
          Thread.sleep(ThreadLocalRandom.current().nextLong(0, 100));
        }
        catch (Exception e)
        {
          // Do Nothing
        }
        finally
        {
          if (Thread.interrupted())
          {
            LOG.info("Was interrupted");
          }
        }
      }
    }

    public void interruptThis()
    {
      if (thisThread != null)
      {
        thisThread.interrupt();
      }
    }
  }

  @Test
  public void testDeadlock() throws IOException, InterruptedException
  {
    receiver = DatagramChannel.open();
    receiver.setOption(StandardSocketOptions.SO_REUSEADDR, true);
    receiver.bind(new InetSocketAddress(42421));
    ExecutorService executor = Executors.newSingleThreadExecutor();
    Sender senderActor = new Sender();
    executor.submit(senderActor);
    while (running)
    {
      LOG.info("Before interrupt");
      senderActor.interruptThis();
      // Sooner or later, you stop seeing this message.
      LOG.info("After interrupt");
      Thread.sleep(ThreadLocalRandom.current().nextLong(0, 100));
    }
  }
}
---------- END SOURCE ----------