kernel/util: Clear list links on removal under KDEBUG.

This way, if someone tries to double-remove an item or do other
invalid things to it, this will crash instead of (silently) corrupting.

headers/private/kernel/util/DoublyLinkedList.h

@@ -528,6 +528,10 @@ DOUBLY_LINKED_LIST_CLASS_NAME::Remove(Element* element)
 			sGetLink(elLink->next)->previous = elLink->previous;
 		else
 			fLast = elLink->previous;
+
+#if DEBUG_DOUBLY_LINKED_LIST
+		elLink->next = elLink->previous = NULL;
+#endif
 	}
 }
 

src/system/kernel/util/list.cpp

@@ -79,6 +79,10 @@ list_remove_link(void *_link)
 
 	link->next->prev = link->prev;
 	link->prev->next = link->next;
+
+#if DEBUG_DOUBLY_LINKED_LIST
+	link->prev = link->next = NULL;
+#endif
 }