commit 821ab588af4566a800d4b5608092ccc1dd3764af
author Ian Rogers <irogers@google.com> Tue Aug 21 17:26:13 2012 -0700
committer Ian Rogers <irogers@google.com> Tue Aug 21 17:53:59 2012 -0700
tree 974e71f5937b1835d9f86f42854c73d793f14204
parent a20bc3bada66210e4fb76352bf29cb3c2b41f7b3

Ensure we fence the writing of clazz to an Object post allocation.

We hold the heap lock during the calloc of an object in the GCed heap.
We do a non-volatile store following this for the clazz, this may lead to a
race where an object is allocated but appears to have no clazz.

Found investigating Bug: 7028104

Change-Id: I390ad4c7b9632127bd27393742be347b84d9269a

vm/oo/Object.h

diff --git a/vm/oo/Object.h b/vm/oo/Object.h
index 4e6103a..2f6fcaf 100644
--- a/vm/oo/Object.h
+++ b/vm/oo/Object.h
@@ -221,7 +221,7 @@
  * void DVM_OBJECT_INIT(Object *obj, ClassObject *clazz_)
  */
 #define DVM_OBJECT_INIT(obj, clazz_) \
-    dvmSetFieldObject(obj, OFFSETOF_MEMBER(Object, clazz), clazz_)
+    dvmSetFieldObjectVolatile(obj, OFFSETOF_MEMBER(Object, clazz), clazz_)
 
 /*
  * Data objects have an Object header followed by their instance data.