--- linux/mm/memory.c	Fri Apr 27 14:23:25 2001
+++ memory.c	Mon May  7 01:30:21 2001
@@ -1428,6 +1428,8 @@
 	struct vm_area_struct * vma;
 
 	vma = find_vma(mm, addr);
+	if(!vma)
+		return -1;
 	write = (vma->vm_flags & VM_WRITE) != 0;
 	if (addr >= end)
 		BUG();