Prevent the call to SparkContext#stop() in the listener bus's thread

Author: tedyu

core/src/main/scala/org/apache/spark/SparkContext.scala

@@ -1694,6 +1694,10 @@ class SparkContext(config: SparkConf) extends Logging with ExecutorAllocationCli
 
   // Shut down the SparkContext.
   def stop() {
+    if (AsynchronousListenerBus.withinListenerThread.value) {
+      throw new SparkException("Cannot stop SparkContext within listener thread of" +
+        " AsynchronousListenerBus")
+    }
     // Use the stopping variable to ensure no contention for the stop scenario.
     // Still track the stopped variable for use elsewhere in the code.
     if (!stopped.compareAndSet(false, true)) {