[WIN32K] Add some validity checks in PDEVOBJ_vReference() and use it instead of explicitly manipulating ppdev->cPdevRefs.

win32ss/gdi/eng/pdevobj.h

@@ -162,6 +162,24 @@ NTAPI
 EngpGetPDEV(
     _In_opt_ PUNICODE_STRING pustrDevice);
 
+FORCEINLINE
+VOID
+PDEVOBJ_vReference(
+    _In_ PPDEVOBJ ppdev)
+{
+    ASSERT(ppdev);
+
+    /* Fail if the PDEV is being destroyed */
+    if (ppdev->cPdevRefs == 0)
+    {
+        ASSERT(FALSE);
+        return;
+    }
+    ASSERT(ppdev->cPdevRefs > 0);
+
+    InterlockedIncrement(&ppdev->cPdevRefs);
+}
+
 VOID
 NTAPI
 PDEVOBJ_vRelease(
@@ -201,11 +219,4 @@ PDEVOBJ_pdmMatchDevMode(
     PPDEVOBJ ppdev,
     PDEVMODEW pdm);
 
-FORCEINLINE
-VOID
-PDEVOBJ_vReference(PPDEVOBJ ppdev)
-{
-    InterlockedIncrement(&ppdev->cPdevRefs);
-}
-
 #endif /* !__WIN32K_PDEVOBJ_H */