Index: /trunk/src/VBox/VMM/VMMR0/HMR0.cpp
===================================================================
--- /trunk/src/VBox/VMM/VMMR0/HMR0.cpp	(revision 49931)
+++ /trunk/src/VBox/VMM/VMMR0/HMR0.cpp	(revision 49932)
@@ -946,4 +946,5 @@
     PHMR0FIRSTRC    pFirstRc = (PHMR0FIRSTRC)pvUser2;
     AssertReturnVoid(g_HvmR0.fGlobalInit);
+    Assert(!RTThreadPreemptIsEnabled(NIL_RTTHREAD));
     hmR0FirstRcSetStatus(pFirstRc, hmR0EnableCpu(pVM, idCpu));
 }