From 176a26ab0dba12d8c053376f32e5accba9e9166a Mon Sep 17 00:00:00 2001
From: schwarze <schwarze@openbsd.org>
Date: Wed, 8 Jun 2022 16:29:12 +0000
Subject: [PATCH] When looking for the next block to tag, we aren't interested
 in children of the current block but really want the next block instead. 
 This fixes a segfault reported by Evan Silberman <evan at jklol dot net> on
 bugs@.

---
 usr.bin/mandoc/mdoc_validate.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/usr.bin/mandoc/mdoc_validate.c b/usr.bin/mandoc/mdoc_validate.c
index 9e681af4b50..aa47566638a 100644
--- a/usr.bin/mandoc/mdoc_validate.c
+++ b/usr.bin/mandoc/mdoc_validate.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mdoc_validate.c,v 1.305 2021/10/04 14:18:42 schwarze Exp $ */
+/* $OpenBSD: mdoc_validate.c,v 1.306 2022/06/08 16:29:12 schwarze Exp $ */
 /*
  * Copyright (c) 2010-2021 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2008-2012 Kristaps Dzonsons <kristaps@bsd.lv>
@@ -1098,7 +1098,8 @@ post_tg(POST_ARGS)
 	/* Find the next node. */
 	n = mdoc->last;
 	for (nn = n; nn != NULL; nn = nn->parent) {
-		if (nn->next != NULL) {
+		if (nn->type != ROFFT_HEAD && nn->type != ROFFT_BODY &&
+		    nn->type != ROFFT_TAIL && nn->next != NULL) {
 			nn = nn->next;
 			break;
 		}
-- 
2.20.1