diff --git a/sys/kern/kern_mutex.c b/sys/kern/kern_mutex.c
index 435cbe753bf7..27df45c10757 100644
--- a/sys/kern/kern_mutex.c
+++ b/sys/kern/kern_mutex.c
@@ -629,7 +629,8 @@ __mtx_lock_sleep(volatile uintptr_t *c, uintptr_t v)
 #ifdef KDTRACE_HOOKS
 		sleep_time -= lockstat_nsecs(&m->lock_object);
 #endif
-		turnstile_wait(ts, mtx_owner(m), TS_EXCLUSIVE_QUEUE);
+		MPASS(owner == mtx_owner(m));
+		turnstile_wait(ts, owner, TS_EXCLUSIVE_QUEUE);
 #ifdef KDTRACE_HOOKS
 		sleep_time += lockstat_nsecs(&m->lock_object);
 		sleep_cnt++;
@@ -1002,7 +1003,7 @@ __mtx_unlock_sleep(volatile uintptr_t *c)
 {
 	struct mtx *m;
 	struct turnstile *ts;
-	uintptr_t tid, v;
+	uintptr_t tid;
 
 	if (SCHEDULER_STOPPED())
 		return;
@@ -1028,12 +1029,12 @@ __mtx_unlock_sleep(volatile uintptr_t *c)
 	 * can be removed from the hash list if it is empty.
 	 */
 	turnstile_chain_lock(&m->lock_object);
+	_mtx_release_lock_quick(m);
 	ts = turnstile_lookup(&m->lock_object);
+	MPASS(ts != NULL);
 	if (LOCK_LOG_TEST(&m->lock_object, opts))
 		CTR1(KTR_LOCK, "_mtx_unlock_sleep: %p contested", m);
-	MPASS(ts != NULL);
 	turnstile_broadcast(ts, TS_EXCLUSIVE_QUEUE);
-	_mtx_release_lock_quick(m);
 
 	/*
 	 * This turnstile is now no longer associated with the mutex.  We can