diff --git a/runtime/thread_list.h b/runtime/thread_list.h
index f97ecd3..df81ad1 100644
--- a/runtime/thread_list.h
+++ b/runtime/thread_list.h
@@ -89,8 +89,8 @@
                !Locks::thread_list_lock_,
                !Locks::thread_suspend_count_lock_);
 
-  // Find an already suspended thread (or self) by its id.
-  Thread* FindThreadByThreadId(uint32_t thin_lock_id);
+  // Find an existing thread (or self) by its thread id (not tid).
+  Thread* FindThreadByThreadId(uint32_t thread_id) REQUIRES(Locks::thread_list_lock_);
 
   // Run a checkpoint on threads, running threads are not suspended but run the checkpoint inside
   // of the suspend check. Returns how many checkpoints that are expected to run, including for