From b81ef55c86817a4ccf18086fd9b7dc3ee49ae415 Mon Sep 17 00:00:00 2001
From: mpi <mpi@openbsd.org>
Date: Wed, 1 Sep 2021 08:06:49 +0000
Subject: [PATCH] Imitate how free(3) behaves and make map_clear() works on
 NULL map.

---
 usr.sbin/btrace/map.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/btrace/map.c b/usr.sbin/btrace/map.c
index b5bb8fb76ef..5624db68069 100644
--- a/usr.sbin/btrace/map.c
+++ b/usr.sbin/btrace/map.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: map.c,v 1.15 2021/09/01 07:35:21 mpi Exp $ */
+/*	$OpenBSD: map.c,v 1.16 2021/09/01 08:06:49 mpi Exp $ */
 
 /*
  * Copyright (c) 2020 Martin Pieuchot <mpi@openbsd.org>
@@ -84,6 +84,9 @@ map_clear(struct map *map)
 {
 	struct mentry *mep;
 
+	if (map == NULL)
+		return;
+
 	while ((mep = RB_MIN(map, map)) != NULL) {
 		RB_REMOVE(map, map, mep);
 		free(mep);
-- 
2.20.1