[SPARK-6492][CORE] SparkContext.stop() can deadlock when DAGSchedulerEventProcessLoop dies

I've added a timeout and retry loop around the SparkContext shutdown code that should fix this deadlock. If a SparkContext shutdown is in progress when another thread comes knocking, it will wait for 10 seconds for the lock, then fall through where the outer loop will re-submit the request.

Author: Ilya Ganelin <ilya.ganelin@capitalone.com>

Closes #5277 from ilganeli/SPARK-6492 and squashes the following commits:

8617a7e [Ilya Ganelin] Resolved merge conflict
2fbab66 [Ilya Ganelin] Added MIMA Exclude
a0e2c70 [Ilya Ganelin] Deleted stale imports
fa28ce7 [Ilya Ganelin] reverted to just having a single stopped
76fc825 [Ilya Ganelin] Updated to use atomic booleans instead of the synchronized vars
6e8a7f7 [Ilya Ganelin] Removing unecessary null check for now since i'm not fixing stop ordering yet
cdf7073 [Ilya Ganelin] [SPARK-6492] Moved stopped=true back to the start of the shutdown sequence so this can be addressed in a seperate PR
7fb795b [Ilya Ganelin] Spacing
b7a0c5c [Ilya Ganelin] Import ordering
df8224f [Ilya Ganelin] Added comment for added lock
343cb94 [Ilya Ganelin] [SPARK-6492] Added timeout/retry logic to fix a deadlock in SparkContext shutdown

1 files changed, 4 insertions, 0 deletions

diff --git a/project/MimaExcludes.scala b/project/MimaExcludes.scala
index 54500f7c27..c2d828f982 100644
--- a/project/MimaExcludes.scala
+++ b/project/MimaExcludes.scala
@@ -60,6 +60,10 @@ object MimaExcludes {
           ) ++ Seq(
             // SPARK-6510 Add a Graph#minus method acting as Set#difference
             ProblemFilters.exclude[MissingMethodProblem]("org.apache.spark.graphx.VertexRDD.minus")
+          ) ++ Seq(
+            // SPARK-6492 Fix deadlock in SparkContext.stop()
+            ProblemFilters.exclude[MissingMethodProblem]("org.apache.spark.SparkContext.org$" +
+                "apache$spark$SparkContext$$SPARK_CONTEXT_CONSTRUCTOR_LOCK")
           )
 
         case v if v.startsWith("1.3") =>