===================================================================
RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/mg/undo.c,v
retrieving revision 1.53
retrieving revision 1.54
diff -u -r1.53 -r1.54
--- src/usr.bin/mg/undo.c	2013/03/25 11:39:38	1.53
+++ src/usr.bin/mg/undo.c	2013/06/01 16:27:56	1.54
@@ -1,4 +1,4 @@
-/* $OpenBSD: undo.c,v 1.53 2013/03/25 11:39:38 florian Exp $ */
+/* $OpenBSD: undo.c,v 1.54 2013/06/01 16:27:56 lum Exp $ */
 /*
  * This file is in the public domain
  */
@@ -390,7 +390,8 @@
 		return (FALSE);
 	bp->b_flag |= BFREADONLY;
 	bclear(bp);
-	popbuf(bp, WNONE);
+	if ((wp = popbuf(bp, WNONE)) == NULL)
+		return (FALSE);
 
 	for (wp = wheadp; wp != NULL; wp = wp->w_wndp) {
 		if (wp->w_bufp == bp) {