[SPARK-3747] TaskResultGetter could incorrectly abort a stage if it c…

…annot get result for a specific task

Author: Reynold Xin <rxin@apache.org>

Closes apache#2599 from rxin/SPARK-3747 and squashes the following commits:

a74c04d [Reynold Xin] Added a line of comment explaining NonFatal
0e8d44c [Reynold Xin] [SPARK-3747] TaskResultGetter could incorrectly abort a stage if it cannot get result for a specific task

core/src/main/scala/org/apache/spark/scheduler/TaskResultGetter.scala

@@ -19,6 +19,8 @@ package org.apache.spark.scheduler
 
 import java.nio.ByteBuffer
 
+import scala.util.control.NonFatal
+
 import org.apache.spark._
 import org.apache.spark.TaskState.TaskState
 import org.apache.spark.serializer.SerializerInstance
@@ -32,7 +34,7 @@ private[spark] class TaskResultGetter(sparkEnv: SparkEnv, scheduler: TaskSchedul
 
   private val THREADS = sparkEnv.conf.getInt("spark.resultGetter.threads", 4)
   private val getTaskResultExecutor = Utils.newDaemonFixedThreadPool(
-    THREADS, "Result resolver thread")
+    THREADS, "task-result-getter")
 
   protected val serializer = new ThreadLocal[SerializerInstance] {
     override def initialValue(): SerializerInstance = {
@@ -70,7 +72,8 @@ private[spark] class TaskResultGetter(sparkEnv: SparkEnv, scheduler: TaskSchedul
           case cnf: ClassNotFoundException =>
             val loader = Thread.currentThread.getContextClassLoader
             taskSetManager.abort("ClassNotFound with classloader: " + loader)
-          case ex: Exception =>
+          // Matching NonFatal so we don't catch the ControlThrowable from the "return" above.
+          case NonFatal(ex) =>
             logError("Exception while getting task result", ex)
             taskSetManager.abort("Exception while getting task result: %s".format(ex))
         }