diff --git a/src/threads/synch.c b/src/threads/synch.c
index f8e6dd3..4933a58 100644
--- a/src/threads/synch.c
+++ b/src/threads/synch.c
@@ -114,13 +114,13 @@ sema_up (struct semaphore *sema)
 
   old_level = intr_disable ();
   if (!list_empty (&sema->waiters))
-  {
-    /* Enforces wake-up of the highest priority thread waiting for the
-       semaphore. */
-    struct list_elem *e = list_min (&sema->waiters, priority_more, NULL);
-    list_remove (e);
-    thread_unblock (list_entry (e, struct thread, elem));
-  }
+    {
+      /* Enforces wake-up of the highest priority thread waiting for the
+         semaphore. */
+      struct list_elem *e = list_min (&sema->waiters, priority_more, NULL);
+      list_remove (e);
+      thread_unblock (list_entry (e, struct thread, elem));
+    }
   sema->value++;
   intr_set_level (old_level);