diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c
index 2ad05ca89a4c..da53c851e511 100644
--- a/lib/libthr/thread/thr_mutex.c
+++ b/lib/libthr/thread/thr_mutex.c
@@ -850,11 +850,8 @@ mutex_self_trylock(struct pthread_mutex *m)
 
 	switch (PMUTEX_TYPE(m->m_flags)) {
 	case PTHREAD_MUTEX_ERRORCHECK:
-	case PTHREAD_MUTEX_ADAPTIVE_NP:
-		ret = EDEADLK;
-		break;
-
 	case PTHREAD_MUTEX_NORMAL:
+	case PTHREAD_MUTEX_ADAPTIVE_NP:
 		ret = EBUSY;
 		break;