Update releasing of locks to update donation information w/ S

src/threads/synch.c

@@ -265,6 +265,18 @@ lock_release (struct lock *lock)
   ASSERT (lock != NULL);
   ASSERT (lock_held_by_current_thread (lock));
 
+  struct thread *current_thread = thread_current ();
+  struct list_elem *tail = list_tail (&current_thread->donors_list);
+  for (struct list_elem *e = list_begin (&current_thread->donors_list);
+       e != tail; e = e->next)
+    {
+      struct thread *donor = list_entry (e, struct thread, donor_elem);
+      if (donor->waiting_lock == lock)
+        list_remove (e);
+    }
+
+  thread_recalculate_priority ();
+
   lock->holder = NULL;
   sema_up (&lock->semaphore);
 }