diff --git a/lib/libthr/thread/thr_mutex.c b/lib/libthr/thread/thr_mutex.c
index ae6e406164a3..ec2893164677 100644
--- a/lib/libthr/thread/thr_mutex.c
+++ b/lib/libthr/thread/thr_mutex.c
@@ -285,8 +285,6 @@ _pthread_mutex_trylock(pthread_mutex_t *mutex)
 {
 	int	ret = 0;
 
-	_thread_sigblock();
-
 	/*
 	 * If the mutex is statically initialized, perform the dynamic
 	 * initialization marking the mutex private (delete safe):
@@ -295,9 +293,6 @@ _pthread_mutex_trylock(pthread_mutex_t *mutex)
 	    (ret = mutex_init(mutex, 1)) == 0)
 		ret = mutex_lock_common(mutex, 1, NULL);
 
-	if (ret != 0)
-		_thread_sigunblock();
-
 	return (ret);
 }
 
@@ -529,8 +524,6 @@ _pthread_mutex_lock(pthread_mutex_t *mutex)
 	if (_thread_initial == NULL)
 		_thread_init();
 
-	_thread_sigblock();
-
 	/*
 	 * If the mutex is statically initialized, perform the dynamic
 	 * initialization marking it private (delete safe):
@@ -539,9 +532,6 @@ _pthread_mutex_lock(pthread_mutex_t *mutex)
 	    ((ret = mutex_init(mutex, 1)) == 0))
 		ret = mutex_lock_common(mutex, 0, NULL);
 
-	if (ret != 0)
-		_thread_sigunblock();
-
 	return (ret);
 }
 
@@ -577,10 +567,7 @@ __pthread_mutex_unlock(pthread_mutex_t * mutex)
 int
 _pthread_mutex_unlock(pthread_mutex_t * mutex)
 {
-	int error;
-	if ((error = mutex_unlock_common(mutex, /* add reference */ 0)) == 0)
-		_thread_sigunblock();
-	return (error);
+	return (mutex_unlock_common(mutex, /* add reference */ 0));
 }
 
 int