diff --git a/winsup/utils/ChangeLog b/winsup/utils/ChangeLog
index 64b530d61..7f980c690 100644
--- a/winsup/utils/ChangeLog
+++ b/winsup/utils/ChangeLog
@@ -1,3 +1,7 @@
+2005-02-27  Christopher Faylor  <cgf@timesys.com>
+
+	* regtool.cc (main): Avoid a SEGV when nothing follows -K.
+
 2005-02-26  Christopher Faylor  <cgf@timesys.com>
 
 	* kill (getsig): Avoid buffer overflow when generating a signal name.
diff --git a/winsup/utils/regtool.cc b/winsup/utils/regtool.cc
index 403923b2d..6954c6556 100644
--- a/winsup/utils/regtool.cc
+++ b/winsup/utils/regtool.cc
@@ -674,7 +674,10 @@ main (int argc, char **_argv)
 	  print_version ();
 	  exit (0);
 	case 'K':
-	  key_sep = *optarg;
+	  if (!optarg)
+	    usage ();
+	  else
+	    key_sep = *optarg;
 	  break;
 	default :
 	  usage ();