8247762: [aarch64] Timeout in .../HeapDumpTestWithActiveProcess.java …

…due to inf. loop in AARCH64CurrentFrameGuess.run()

Reviewed-by: cjplummer, aph

src/jdk.hotspot.agent/share/classes/sun/jvm/hotspot/runtime/aarch64/AARCH64CurrentFrameGuess.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2015, 2019, Red Hat Inc.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
@@ -138,7 +138,16 @@ public boolean run(long regionInBytesToSearch) {
                 setValues(curSP, null, pc);
                 return true;
               }
+              Frame oldFrame = frame;
               frame = frame.sender(map);
+              if (frame.getSP().lessThanOrEqual(oldFrame.getSP())) {
+                // Frame points to itself or to a location in the wrong direction.
+                // Break the loop and move on to next offset.
+                if (DEBUG) {
+                  System.out.println("CurrentFrameGuess: frame <= oldFrame: " + frame);
+                }
+                break;
+              }
             }
           } catch (Exception e) {
             if (DEBUG) {