diff --git a/core/src/main/scala/org/apache/spark/scheduler/Pool.scala b/core/src/main/scala/org/apache/spark/scheduler/Pool.scala
index 4cd13e2feaeb10ae687abf3313459567c7b86dab..a79e71ec7c9bf09601fe91f1b142ca16340dc1d6 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/Pool.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/Pool.scala
@@ -55,6 +55,8 @@ private[spark] class Pool(
         new FairSchedulingAlgorithm()
       case SchedulingMode.FIFO =>
         new FIFOSchedulingAlgorithm()
+      case _ =>
+        throw new IllegalArgumentException(s"Unsupported spark.scheduler.mode: $schedulingMode")
     }
   }
 
diff --git a/core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala b/core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala
index c3159188d9f03714b8f2c04a853bbd4dd9c56107..f31ec2af4ebd6deb0eb4270fbd99cd8c4cb3ef43 100644
--- a/core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala
+++ b/core/src/main/scala/org/apache/spark/scheduler/TaskSchedulerImpl.scala
@@ -135,6 +135,8 @@ private[spark] class TaskSchedulerImpl(
           new FIFOSchedulableBuilder(rootPool)
         case SchedulingMode.FAIR =>
           new FairSchedulableBuilder(rootPool, conf)
+        case _ =>
+          throw new IllegalArgumentException(s"Unsupported spark.scheduler.mode: $schedulingMode")
       }
     }
     schedulableBuilder.buildPools()