From 7a6f726ddcf5d20758d607993ef33aa8fbd11d96 Mon Sep 17 00:00:00 2001
From: kib <kib@FreeBSD.org>
Date: Mon, 30 Sep 2019 14:16:44 +0000
Subject: [PATCH] MFC r352620, MFS12 r352892: Fix destruction of the robust
 mutexes.

Approved by:	re (gjb)
---
 lib/libthr/thread/thr_mutex.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c
index dc09f539add..57984ef6d0e 100644
--- a/lib/libthr/thread/thr_mutex.c
+++ b/lib/libthr/thread/thr_mutex.c
@@ -474,7 +474,11 @@ _thr_mutex_destroy(pthread_mutex_t *mutex)
 		if (m == THR_PSHARED_PTR) {
 			m1 = __thr_pshared_offpage(mutex, 0);
 			if (m1 != NULL) {
-				mutex_assert_not_owned(_get_curthread(), m1);
+				if ((uint32_t)m1->m_lock.m_owner !=
+				    UMUTEX_RB_OWNERDEAD) {
+					mutex_assert_not_owned(
+					    _get_curthread(), m1);
+				}
 				__thr_pshared_destroy(mutex);
 			}
 			*mutex = THR_MUTEX_DESTROYED;