--- mm/fadvise.c	2004-01-19 20:09:03.000000000 -0800
+++ mm/fadvise.c-new	2004-02-12 22:33:32.000000000 -0800
@@ -33,7 +33,7 @@
 		return -EBADF;
 
 	mapping = file->f_mapping;
-	if (!mapping) {
+	if (!mapping || len < 0) {
 		ret = -EINVAL;
 		goto out;
 	}