Index: /trunk/src/VBox/Additions/common/VBoxGuestLib/VBoxGuestR3LibModule.cpp
===================================================================
--- /trunk/src/VBox/Additions/common/VBoxGuestLib/VBoxGuestR3LibModule.cpp	(revision 29394)
+++ /trunk/src/VBox/Additions/common/VBoxGuestLib/VBoxGuestR3LibModule.cpp	(revision 29395)
@@ -58,4 +58,5 @@
 
     vmmdevInitRequest(&pReq->header, VMMDevReq_RegisterSharedModule);
+    pReq->header.size   = RT_OFFSETOF(VMMDevSharedModuleRegistrationRequest, aRegions[cRegions]);
     pReq->GCBaseAddr    = GCBaseAddr;
     pReq->cbModule      = cbModule;