# HG changeset patch
# User shshahma
# Date 1503552422 14400
# Node ID 96e9e479ff8a6dff37249d045e9676e206005f7b
# Parent  ea7502500b78880cf7da084d5aa5dc5176713b25
8180855: Null pointer dereference in OopMapSet::all_do of oopMap.cpp:394
Summary: Check for possible null-point dereference.
Reviewed-by: kvn

diff -r ea7502500b78 -r 96e9e479ff8a src/share/vm/compiler/oopMap.cpp
--- a/src/share/vm/compiler/oopMap.cpp	Wed Aug 23 04:07:36 2017 -0400
+++ b/src/share/vm/compiler/oopMap.cpp	Thu Aug 24 01:27:02 2017 -0400
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2014, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2017, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -389,17 +389,16 @@
         omv = oms.current();
         oop* loc = fr->oopmapreg_to_location(omv.reg(),reg_map);
         if ( loc != NULL ) {
+          oop *derived_loc = loc;
           oop *base_loc    = fr->oopmapreg_to_location(omv.content_reg(), reg_map);
-          oop *derived_loc = loc;
-          oop val = *base_loc;
-          if (val == (oop)NULL || Universe::is_narrow_oop_base(val)) {
-            // Ignore NULL oops and decoded NULL narrow oops which
-            // equal to Universe::narrow_oop_base when a narrow oop
-            // implicit null check is used in compiled code.
-            // The narrow_oop_base could be NULL or be the address
-            // of the page below heap depending on compressed oops mode.
-          } else
+          // Ignore NULL oops and decoded NULL narrow oops which
+          // equal to Universe::narrow_oop_base when a narrow oop
+          // implicit null check is used in compiled code.
+          // The narrow_oop_base could be NULL or be the address
+          // of the page below heap depending on compressed oops mode.
+          if (base_loc != NULL && *base_loc != (oop)NULL && !Universe::is_narrow_oop_base(*base_loc)) {
             derived_oop_fn(base_loc, derived_loc);
+          }
         }
         oms.next();
       }  while (!oms.is_done());