--- 2.3.99-pre3aa1-alpha/include/linux/swap.h.~1~	Wed Mar 29 18:16:18 2000
+++ 2.3.99-pre3aa1-alpha/include/linux/swap.h	Thu Mar 30 16:41:45 2000
@@ -173,6 +173,8 @@
 
 #define	lru_cache_del(page)			\
 do {						\
+	if (!PageLocked(page))			\
+		BUG();				\
 	spin_lock(&pagemap_lru_lock);		\
 	list_del(&(page)->lru);			\
 	nr_lru_pages--;				\