diff --git a/winsup/cygwin/ChangeLog b/winsup/cygwin/ChangeLog
index 1949c5af3..681b809c4 100644
--- a/winsup/cygwin/ChangeLog
+++ b/winsup/cygwin/ChangeLog
@@ -1,3 +1,7 @@
+2001-11-05  Corinna Vinschen  <corinna@vinschen.de>
+
+	* mmap.cc (mmap_record::find_empty): Add input parameter check.
+
 2001-11-04  Christopher Faylor  <cgf@redhat.com>
 
 	* dtable.cc (dtable::build_fhandler): Fix debug_printf to avoid SEGV
diff --git a/winsup/cygwin/mmap.cc b/winsup/cygwin/mmap.cc
index ab36a5234..884941ae4 100644
--- a/winsup/cygwin/mmap.cc
+++ b/winsup/cygwin/mmap.cc
@@ -109,6 +109,8 @@ mmap_record::find_empty (DWORD pages)
   DWORD mapped_pages = PAGE_CNT (size_to_map_);
   DWORD start;
 
+  if (pages > mapped_pages)
+    return (DWORD)-1;
   for (start = 0; start <= mapped_pages - pages; ++start)
     if (!MAP_ISSET (start))
       {