Index: /trunk/include/iprt/semaphore.h
===================================================================
--- /trunk/include/iprt/semaphore.h	(revision 80529)
+++ /trunk/include/iprt/semaphore.h	(revision 80530)
@@ -663,5 +663,5 @@
  *
  * @remarks The fast mutexes has sideeffects on IRQL on Windows hosts.  So use
- *          with care and test on windows with driver verifier.
+ *          with care and test on windows with the driver verifier enabled.
  *
  * @{ */
@@ -689,8 +689,4 @@
 /**
  * Request ownership of a fast mutex semaphore.
- *
- * The same thread may request a mutex semaphore multiple times,
- * a nested counter is kept to make sure it's released on the right
- * RTSemMutexRelease() call.
  *
  * @returns iprt status code.
Index: /trunk/src/VBox/Runtime/r0drv/nt/semmutex-r0drv-nt.cpp
===================================================================
--- /trunk/src/VBox/Runtime/r0drv/nt/semmutex-r0drv-nt.cpp	(revision 80529)
+++ /trunk/src/VBox/Runtime/r0drv/nt/semmutex-r0drv-nt.cpp	(revision 80530)
@@ -231,6 +231,6 @@
     return pThis->Mutex && pThis->Mutex->Owner != NULL;
 #else
-    return KeReadStateMutex(&pThis->Mutex) == 1;
-#endif
-}
-
+    return KeReadStateMutex(&pThis->Mutex) == 0;
+#endif
+}
+