To prevent infinite recursion while expanding eqn(7) definitions,

we must not reset the recursion counter when moving beyond the end
of the *previous* expansion, but we may only do so when moving
beyond the rightmost position reached by *any* expansion in the
current equation.  This matters because definitions can nest;
consider:

.EQ
define inner "content"
define outer "inner outer"
outer
.EN

This endless loop was found by tb@ using afl(1).

Incidentally, GNU eqn(1) also performs an infinite loop in this
situation and then crashes when memory runs out, but that's not an
excuse for nasty behaviour of mandoc(1).

While here, consistently print the expanded content even when the
expansion is finally truncated.  While that is not likely to help
end-users, it may help authors of eqn(7) code to understand what's
going on.  Besides, it sends a very clear signal that something is
amiss, which was easy to miss in the past unless people
enabled -W error or used -T lint.

5 files changed, 95 insertions, 20 deletions

diff --git a/eqn.c b/eqn.c
index 27f5cac3..45124c68 100644
--- a/eqn.c
+++ b/eqn.c
@@ -1,7 +1,8 @@
-/*	$Id: eqn.c,v 1.84 2020/01/08 12:16:24 schwarze Exp $ */
+/* $Id: eqn.c,v 1.85 2022/04/13 20:26:19 schwarze Exp $ */
 /*
+ * Copyright (c) 2014, 2015, 2017, 2018, 2020, 2022
+ *               Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2011, 2014 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2014,2015,2017,2018,2020 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -375,19 +376,17 @@ eqn_def_find(struct eqn_node *ep)
 static enum eqn_tok
 eqn_next(struct eqn_node *ep, enum parse_mode mode)
 {
-	static int	 last_len, lim;
-
 	struct eqn_def	*def;
 	size_t		 start;
-	int		 diff, i, quoted;
+	int		 diff, i, newlen, quoted;
 	enum eqn_tok	 tok;
 
 	/*
 	 * Reset the recursion counter after advancing
-	 * beyond the end of the previous substitution.
+	 * beyond the end of the rightmost substitution.
 	 */
-	if (ep->end - ep->data >= last_len)
-		lim = 0;
+	if (ep->end - ep->data >= ep->sublen)
+		ep->subcnt = 0;
 
 	ep->start = ep->end;
 	quoted = mode == MODE_QUOTED;
@@ -434,10 +433,10 @@ eqn_next(struct eqn_node *ep, enum parse_mode mode)
 			return EQN_TOK__MAX;
 		if ((def = eqn_def_find(ep)) == NULL)
 			break;
-		if (++lim > EQN_NEST_MAX) {
+		if (++ep->subcnt > EQN_NEST_MAX) {
 			mandoc_msg(MANDOCERR_ROFFLOOP,
 			    ep->node->line, ep->node->pos, NULL);
-			return EQN_TOK_EOF;
+			break;
 		}
 
 		/* Replace a defined name with its string value. */
@@ -446,12 +445,15 @@ eqn_next(struct eqn_node *ep, enum parse_mode mode)
 			ep->sz += diff;
 			ep->data = mandoc_realloc(ep->data, ep->sz + 1);
 			ep->start = ep->data + start;
+			ep->sublen += diff;
 		}
 		if (diff)
 			memmove(ep->start + def->valsz, ep->start + ep->toksz,
 			    strlen(ep->start + ep->toksz) + 1);
 		memcpy(ep->start, def->val, def->valsz);
-		last_len = ep->start - ep->data + def->valsz;
+		newlen = ep->start - ep->data + def->valsz;
+		if (ep->sublen < newlen)
+			ep->sublen = newlen;
 	}
 	if (mode != MODE_TOK)
 		return quoted ? EQN_TOK_QUOTED : EQN_TOK__MAX;
@@ -678,6 +680,8 @@ eqn_parse(struct eqn_node *ep)
 		return;
 
 	ep->start = ep->end = ep->data;
+	ep->sublen = 0;
+	ep->subcnt = 0;
 
 next_tok:
 	tok = eqn_next(ep, MODE_TOK);
diff --git a/eqn_parse.h b/eqn_parse.h
index a2a4e6fd..63d7c395 100644
--- a/eqn_parse.h
+++ b/eqn_parse.h
@@ -1,7 +1,7 @@
-/*	$Id: eqn_parse.h,v 1.3 2018/12/14 06:33:14 schwarze Exp $ */
+/* $Id: eqn_parse.h,v 1.4 2022/04/13 20:26:19 schwarze Exp $ */
 /*
+ * Copyright (c) 2014, 2017, 2018, 2022 Ingo Schwarze <schwarze@openbsd.org>
  * Copyright (c) 2011 Kristaps Dzonsons <kristaps@bsd.lv>
- * Copyright (c) 2014, 2017, 2018 Ingo Schwarze <schwarze@openbsd.org>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -32,6 +32,8 @@ struct	eqn_node {
 	size_t		  defsz;   /* Number of definitions. */
 	size_t		  sz;      /* Length of the source code. */
 	size_t		  toksz;   /* Length of the current token. */
+	int		  sublen;  /* End of rightmost substitution, so far. */
+	int		  subcnt;  /* Number of recursive substitutions. */
 	int		  gsize;   /* Default point size. */
 	int		  delim;   /* In-line delimiters enabled. */
 	char		  odelim;  /* In-line opening delimiter. */
diff --git a/regress/eqn/define/infinite.in b/regress/eqn/define/infinite.in
index 420e6376..31a3f646 100644
--- a/regress/eqn/define/infinite.in
+++ b/regress/eqn/define/infinite.in
@@ -1,5 +1,5 @@
-.\" $OpenBSD: infinite.in,v 1.2 2017/07/04 14:53:23 schwarze Exp $
-.Dd $Mdocdate: July 4 2017 $
+.\" $OpenBSD: infinite.in,v 1.3 2022/04/13 20:19:18 schwarze Exp $
+.Dd $Mdocdate: April 13 2022 $
 .Dt DEFINE-INFINITE 1
 .Os
 .Sh NAME
@@ -29,3 +29,11 @@ trailing position:
 define key 'prefix key' key
 .EN
 eol
+.Pp
+nested expansion:
+.EQ
+define inner "content"
+define outer "inner outer"
+outer
+.EN
+eol
diff --git a/regress/eqn/define/infinite.out_ascii b/regress/eqn/define/infinite.out_ascii
index 7219ce5b..a756abbb 100644
--- a/regress/eqn/define/infinite.out_ascii
+++ b/regress/eqn/define/infinite.out_ascii
@@ -4,12 +4,72 @@ NNAAMMEE
      ddeeffiinnee--iinnffiinniittee - infinite recursion in define statements
 
 DDEESSCCRRIIPPTTIIOONN
-     alone: eol
+     alone: _k_e_y eol
 
-     leading position: eol
+     leading position: _k_e_y _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x eol
 
-     middle position: eol
+     middle position: _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _k_e_y
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x
+     _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x _s_u_f_f_i_x eol
 
-     trailing position: eol
+     trailing position: _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x _p_r_e_f_i_x
+     _p_r_e_f_i_x _k_e_y eol
 
-OpenBSD                          July 4, 2017                          OpenBSD
+     nested expansion: _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t
+     _c_o_n_t_e_n_t _c_o_n_t_e_n_t _c_o_n_t_e_n_t _o_u_t_e_r eol
+
+OpenBSD                         April 13, 2022                         OpenBSD
diff --git a/regress/eqn/define/infinite.out_lint b/regress/eqn/define/infinite.out_lint
index 43089bb3..245aa523 100644
--- a/regress/eqn/define/infinite.out_lint
+++ b/regress/eqn/define/infinite.out_lint
@@ -2,3 +2,4 @@ mandoc: infinite.in:10:2: ERROR: input stack limit exceeded, infinite loop?
 mandoc: infinite.in:16:2: ERROR: input stack limit exceeded, infinite loop?
 mandoc: infinite.in:22:2: ERROR: input stack limit exceeded, infinite loop?
 mandoc: infinite.in:28:2: ERROR: input stack limit exceeded, infinite loop?
+mandoc: infinite.in:34:2: ERROR: input stack limit exceeded, infinite loop?