--- 2.3.14-pre2-rawio/mm/memory.c.~1~	Thu Aug 12 02:53:25 1999
+++ 2.3.14-pre2-rawio/mm/memory.c	Fri Aug 20 13:21:36 1999
@@ -411,18 +411,17 @@
  * Given a physical address, is there a useful struct page pointing to it?
  */
 
-static struct page * get_page_map(unsigned long page)
+static int get_page_map(unsigned long page, struct page ** map)
 {
-	struct page *map;
-	
+	*map = NULL;
 	if (MAP_NR(page) >= max_mapnr)
-		return 0;
+		return 1;
 	if (page == ZERO_PAGE(page))
 		return 0;
-	map = mem_map + MAP_NR(page);
-	if (PageReserved(map))
+	*map = mem_map + MAP_NR(page);
+	if (PageReserved(*map))
 		return 0;
-	return map;
+	return 1;
 }
 
 /*
@@ -484,7 +483,12 @@
 			map = NULL;
 			goto retry;
 		}
-		map = get_page_map(page);
+		if (!get_page_map(page, &map))
+		{
+			dprintk(KERN_WARNING
+				"Forbidden page_map in map_user_kiobuf\n");
+			goto out_unlock_page_table;
+		}
 		if (map) {
 			if (TryLockPage(map)) {
 				goto retry;
@@ -504,6 +508,8 @@
 	dprintk ("map_user_kiobuf: end OK\n");
 	return 0;
 
+ out_unlock_page_table:
+	spin_unlock(&mm->page_table_lock);
  out_unlock:
 	up(&mm->mmap_sem);
 	unmap_kiobuf(iobuf);