Index: uspace/drv/uhci-hcd/utils/malloc32.h
===================================================================
--- uspace/drv/uhci-hcd/utils/malloc32.h	(revision 171cd8807faa358a638aa96f6a3e8ed1290ed44f)
+++ uspace/drv/uhci-hcd/utils/malloc32.h	(revision 13b9cb5e3bb9b10afeeaffc39c2633bd8ae64bc9)
@@ -50,4 +50,7 @@
 static inline uintptr_t addr_to_phys(void *addr)
 {
+	if (addr == NULL)
+		return 0;
+
 	uintptr_t result;
 	int ret = as_get_physical_mapping(addr, &result);