diff --git a/library/threading.c b/library/threading.c
index 81c1075..55091e8 100644
--- a/library/threading.c
+++ b/library/threading.c
@@ -32,7 +32,7 @@
 #if defined(MBEDTLS_THREADING_PTHREAD)
 static void threading_mutex_init_pthread( mbedtls_threading_mutex_t *mutex )
 {
-    if( mutex == NULL || mutex->is_valid )
+    if( mutex == NULL )
         return;
 
     mutex->is_valid = pthread_mutex_init( &mutex->mutex, NULL ) == 0;