From 182f10ae1a67d6e891aab6320309b0a436564adf Mon Sep 17 00:00:00 2001
From: kvn <unknown>
Date: Tue, 11 Jan 2011 20:26:13 -0800
Subject: [PATCH] 7011386: race in objArrayKlass::array_klass_impl Summary:
 Move _lower_dimension field initialization before _higher_dimension and add
 storestore barrier. Reviewed-by: dholmes, iveresov, never

---
 src/share/vm/oops/arrayKlass.hpp     | 6 +++---
 src/share/vm/oops/objArrayKlass.cpp  | 5 +++--
 src/share/vm/oops/typeArrayKlass.cpp | 3 ++-
 src/share/vm/runtime/vmStructs.cpp   | 6 +++---
 4 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/share/vm/oops/arrayKlass.hpp b/src/share/vm/oops/arrayKlass.hpp
index 4b504ec47..dff8363b2 100644
--- a/src/share/vm/oops/arrayKlass.hpp
+++ b/src/share/vm/oops/arrayKlass.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -36,8 +36,8 @@ class arrayKlass: public Klass {
   friend class VMStructs;
  private:
   int      _dimension;         // This is n'th-dimensional array.
-  klassOop _higher_dimension;  // Refers the (n+1)'th-dimensional array (if present).
-  klassOop _lower_dimension;   // Refers the (n-1)'th-dimensional array (if present).
+  volatile klassOop _higher_dimension;  // Refers the (n+1)'th-dimensional array (if present).
+  volatile klassOop _lower_dimension;   // Refers the (n-1)'th-dimensional array (if present).
   int      _vtable_len;        // size of vtable for this klass
   juint    _alloc_size;        // allocation profiling support
   oop      _component_mirror;  // component type, as a java/lang/Class
diff --git a/src/share/vm/oops/objArrayKlass.cpp b/src/share/vm/oops/objArrayKlass.cpp
index 3233a4d22..d31d710bc 100644
--- a/src/share/vm/oops/objArrayKlass.cpp
+++ b/src/share/vm/oops/objArrayKlass.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -235,8 +235,9 @@ klassOop objArrayKlass::array_klass_impl(objArrayKlassHandle this_oop, bool or_n
           objArrayKlassKlass::cast(Universe::objArrayKlassKlassObj())->
           allocate_objArray_klass(dimension + 1, this_oop, CHECK_NULL);
         ak = objArrayKlassHandle(THREAD, new_klass);
-        this_oop->set_higher_dimension(ak());
         ak->set_lower_dimension(this_oop());
+        OrderAccess::storestore();
+        this_oop->set_higher_dimension(ak());
         assert(ak->oop_is_objArray(), "incorrect initialization of objArrayKlass");
       }
     }
diff --git a/src/share/vm/oops/typeArrayKlass.cpp b/src/share/vm/oops/typeArrayKlass.cpp
index 8d317dff9..99d3f65cb 100644
--- a/src/share/vm/oops/typeArrayKlass.cpp
+++ b/src/share/vm/oops/typeArrayKlass.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2011, 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
@@ -179,6 +179,7 @@ klassOop typeArrayKlass::array_klass_impl(typeArrayKlassHandle h_this, bool or_n
           dimension + 1, h_this, CHECK_NULL);
         h_ak = objArrayKlassHandle(THREAD, oak);
         h_ak->set_lower_dimension(h_this());
+        OrderAccess::storestore();
         h_this->set_higher_dimension(h_ak());
         assert(h_ak->oop_is_objArray(), "incorrect initialization of objArrayKlass");
       }
diff --git a/src/share/vm/runtime/vmStructs.cpp b/src/share/vm/runtime/vmStructs.cpp
index 2d440e58f..30973292d 100644
--- a/src/share/vm/runtime/vmStructs.cpp
+++ b/src/share/vm/runtime/vmStructs.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2011, 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
@@ -219,8 +219,8 @@ static inline uint64_t cast_uint64_t(size_t x)
   volatile_nonstatic_field(oopDesc,            _metadata._compressed_klass,                   narrowOop)                             \
      static_field(oopDesc,                     _bs,                                           BarrierSet*)                           \
   nonstatic_field(arrayKlass,                  _dimension,                                    int)                                   \
-  nonstatic_field(arrayKlass,                  _higher_dimension,                             klassOop)                              \
-  nonstatic_field(arrayKlass,                  _lower_dimension,                              klassOop)                              \
+  volatile_nonstatic_field(arrayKlass,         _higher_dimension,                             klassOop)                              \
+  volatile_nonstatic_field(arrayKlass,         _lower_dimension,                              klassOop)                              \
   nonstatic_field(arrayKlass,                  _vtable_len,                                   int)                                   \
   nonstatic_field(arrayKlass,                  _alloc_size,                                   juint)                                 \
   nonstatic_field(arrayKlass,                  _component_mirror,                             oop)                                   \
-- 
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