Changeset 8665 in vbox for trunk/src/VBox/Main/VirtualBoxBase.cpp

Timestamp:

May 7, 2008 3:23:25 PM (17 years ago)

Author:

vboxsync

Message:

Use must use atomic compare-and-exchange logic here to be 100% correct.

File:

• trunk/src/VBox/Main/VirtualBoxBase.cpp (modified) (1 diff)

trunk/src/VBox/Main/VirtualBoxBase.cpp

@@ -66 +66 @@
 RWLockHandle *VirtualBoxBaseNEXT_base::lockHandle() const
 {
-    /* lasy initialization */
-    if (!mObjectLock)
-        mObjectLock = new RWLockHandle;
+    /* lazy initialization */
+    if (RT_UNLIKELY(!mObjectLock))
+    {
+        AssertCompile (sizeof (RWLockHandle *) == sizeof (void *));
+        RWLockHandle *objLock = new RWLockHandle;
+        if (!ASMAtomicCmpXchgPtr ((void * volatile *) &mObjectLock, objLock, NULL))
+        {
+            delete objLock;
+            objLock = (RWLockHandle *) ASMAtomicReadPtr ((void * volatile *) &mObjectLock);
+        }
+        return objLock;
+    }
     return mObjectLock;
 }