Index: /trunk/src/VBox/Devices/Graphics/DevVGA_VDMA.cpp
===================================================================
--- /trunk/src/VBox/Devices/Graphics/DevVGA_VDMA.cpp	(revision 58699)
+++ /trunk/src/VBox/Devices/Graphics/DevVGA_VDMA.cpp	(revision 58700)
@@ -3205,4 +3205,6 @@
     PVGASTATE pVGAState = PPDMIDISPLAYVBVACALLBACKS_2_PVGASTATE(pInterface);
     struct VBOXVDMAHOST *pVdma = pVGAState->pVdma;
+    if (pVdma == NULL)
+        return VERR_INVALID_STATE;
     pCmd->CalloutList.List.pNext = NULL;
     return vdmaVBVACtlOpaqueHostSubmit(pVdma, pCmd, cbCmd, pfnCompletion, pvCompletion);
@@ -3282,4 +3284,6 @@
     PVGASTATE pVGAState = PPDMIDISPLAYVBVACALLBACKS_2_PVGASTATE(pInterface);
     struct VBOXVDMAHOST *pVdma = pVGAState->pVdma;
+    if (pVdma == NULL)
+        return VERR_INVALID_STATE;
     VBOXCMDVBVA_CMDHOSTCTL_SYNC Data;
     Data.pVdma = pVdma;