Found one Java-level deadlock:
=============================
"repeater:26224-54663-1-thread-15":
  waiting for ownable synchronizer 7bb547150, (a java.util.concurrent.locks.ReentrantLock$NonfairSync),
  which is held by "repeater:26224-54663-1-thread-13"
"repeater:26224-54663-1-thread-13":
  waiting to lock monitor 1149b9cb8 (object 7bb546f88, a com.sun.net.ssl.internal.ssl.SSLSocketImpl),
  which is held by "repeater:26224-54663-1-thread-15"

Java stack information for the threads listed above:
===================================================
"repeater:26224-54663-1-thread-15":
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <7bb547150> (a java.util.concurrent.locks.ReentrantLock$NonfairSync)
        at java.util.concurrent.locks.LockSupport.park(LockSupport.java:156)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:811)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:842)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1178)
        at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:186)
        at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:262)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:751)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:624)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.sendAlert(SSLSocketImpl.java:1877)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.warning(SSLSocketImpl.java:1715)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.closeInternal(SSLSocketImpl.java:1483)
        - locked <7bb546f88> (a com.sun.net.ssl.internal.ssl.SSLSocketImpl)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.recvAlert(SSLSocketImpl.java:1821)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:1019)
        - locked <7bb546f88> (a com.sun.net.ssl.internal.ssl.SSLSocketImpl)
        - locked <7bb547170> (a java.lang.Object)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.readDataRecord(SSLSocketImpl.java:820)
        at com.sun.net.ssl.internal.ssl.AppInputStream.read(AppInputStream.java:75)
        - locked <7bb547e88> (a com.sun.net.ssl.internal.ssl.AppInputStream)
        at java.io.InputStream.read(InputStream.java:82)
        at com.atlassian.tunnel.tunnel.Repeater.run(Repeater.java:62)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:680)
"repeater:26224-54663-1-thread-13":
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.getConnectionState(SSLSocketImpl.java:601)
        - waiting to lock <7bb546f88> (a com.sun.net.ssl.internal.ssl.SSLSocketImpl)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.isClosed(SSLSocketImpl.java:1328)
        at java.net.Socket.getTcpNoDelay(Socket.java:877)
        at com.sun.net.ssl.internal.ssl.BaseSSLSocketImpl.getTcpNoDelay(BaseSSLSocketImpl.java:325)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecordInternal(SSLSocketImpl.java:770)
        at com.sun.net.ssl.internal.ssl.SSLSocketImpl.writeRecord(SSLSocketImpl.java:753)
        at com.sun.net.ssl.internal.ssl.AppOutputStream.write(AppOutputStream.java:100)
        - locked <7bb54c370> (a com.sun.net.ssl.internal.ssl.AppOutputStream)
        at com.atlassian.tunnel.tunnel.Repeater.run(Repeater.java:68)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:439)
        at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
        at java.util.concurrent.FutureTask.run(FutureTask.java:138)
        at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
        at java.lang.Thread.run(Thread.java:680)