[求助]spark程序正常运行，最后报个nio的错误

ERROR network.ConnectionManager: Corresponding SendingConnection to ConnectionManagerId(dn3.9961.bj,41242) not found
15/01/08 17:46:12 INFO network.ConnectionManager: Key not valid ? sun.nio.ch.SelectionKeyImpl@2b90cc9
15/01/08 17:46:12 INFO network.ConnectionManager: key already cancelled ? sun.nio.ch.SelectionKeyImpl@2b90cc9
java.nio.channels.CancelledKeyException
      at org.apache.spark.network.ConnectionManager.run(ConnectionManager.scala:392)
      at org.apache.spark.network.ConnectionManager$$anon$4.run(ConnectionManager.scala:145)
15/01/08 17:46:12 INFO network.ConnectionManager: Key not valid ? sun.nio.ch.SelectionKeyImpl@70b6e675
15/01/08 17:46:12 INFO network.ConnectionManager: key already cancelled ? sun.nio.ch.SelectionKeyImpl@70b6e675
java.nio.channels.CancelledKeyException
      at org.apache.spark.network.ConnectionManager.run(ConnectionManager.scala:316)
      at org.apache.spark.network.ConnectionManager$$anon$4.run(ConnectionManager.scala:145)
15/01/08 17:46:12 INFO spark.MapOutputTrackerMasterActor: MapOutputTrackerActor stopped!
15/01/08 17:46:12 INFO network.ConnectionManager: Selector thread was interrupted!
15/01/08 17:46:12 INFO network.ConnectionManager: ConnectionManager stopped
15/01/08 17:46:12 INFO storage.MemoryStore: MemoryStore cleared
15/01/08 17:46:12 INFO storage.BlockManager: BlockManager stopped
15/01/08 17:46:12 INFO storage.BlockManagerMaster: BlockManagerMaster stopped

spark程序正常执行完成，最后抱着个错误。不知道什么原因，哪位大牛知道，请指点下。