Index: linux-2.6/include/linux/mm.h
===================================================================
--- linux-2.6.orig/include/linux/mm.h	2007-09-16 20:07:33.000000000 -0700
+++ linux-2.6/include/linux/mm.h	2007-09-16 20:09:40.000000000 -0700
@@ -343,11 +343,13 @@ typedef void compound_page_dtor(struct p
 static inline void set_compound_page_dtor(struct page *page,
 						compound_page_dtor *dtor)
 {
+	BUG_ON(PageVmalloc(page));
 	page[1].lru.next = (void *)dtor;
 }
 
 static inline compound_page_dtor *get_compound_page_dtor(struct page *page)
 {
+	BUG_ON(PageVMalloc(page));
 	return (compound_page_dtor *)page[1].lru.next;
 }
 
@@ -355,11 +357,13 @@ static inline int compound_order(struct 
 {
 	if (!PageHead(page))
 		return 0;
+	BUG_ON(PageVmalloc(page));
 	return (unsigned long)page[1].lru.prev;
 }
 
 static inline void set_compound_order(struct page *page, unsigned long order)
 {
+	BUG_ON(PageVmalloc(page));
 	page[1].lru.prev = (void *)order;
 }