diff --git a/libgfortran/ChangeLog b/libgfortran/ChangeLog
index e94df2c75bd..8a7b66c7351 100644
--- a/libgfortran/ChangeLog
+++ b/libgfortran/ChangeLog
@@ -1,3 +1,9 @@
+2017-12-29  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
+
+	PR libgfortran/83613
+	* io/unit.c (init_units): Don't forget to unlock the unit locks
+	after being inserted.
+
 2017-12-29  Jerry DeLisle  <jvdelisle@gcc.gnu.org>
 
 	PR libgfortran/83560
diff --git a/libgfortran/io/unit.c b/libgfortran/io/unit.c
index 2ca8525fbec..a655665aa8a 100644
--- a/libgfortran/io/unit.c
+++ b/libgfortran/io/unit.c
@@ -707,7 +707,9 @@ init_units (void)
     }
   /* The default internal units.  */
   u = insert_unit (GFC_INTERNAL_UNIT);
+  __gthread_mutex_unlock (&u->lock);
   u = insert_unit (GFC_INTERNAL_UNIT4);
+  __gthread_mutex_unlock (&u->lock);
 }