Index: src/core/org/apache/jmeter/control/GenericController.java
===================================================================
--- src/core/org/apache/jmeter/control/GenericController.java	(revision 1166154)
+++ src/core/org/apache/jmeter/control/GenericController.java	(working copy)
@@ -181,7 +181,14 @@
      * @throws NextIsNullException
      */
     protected Sampler nextIsAController(Controller controller) throws NextIsNullException {
-        Sampler sampler = controller.next();
+        Sampler sampler = null;
+        try {
+            sampler = controller.next();
+        } catch (StackOverflowError soe) {
+            // Special case: see Bug 50618
+            log.info("StackOverflowError detected");
+            throw new NextIsNullException();
+        }
         if (sampler == null) {
             currentReturnedNull(controller);
             sampler = next();