diff --git a/server/robotserver/coroutine.cc b/server/robotserver/coroutine.cc
index d9bc59c2..f33805af 100644
--- a/server/robotserver/coroutine.cc
+++ b/server/robotserver/coroutine.cc
@@ -135,7 +135,11 @@ void TimerPromise::DoAwait()
          [self] (int event, const a8::Args* args) mutable
          {
              if (event == a8::TIMER_EXEC_EVENT) {
-
+                 for (auto notifyer : self->notifyers_) {
+                     if (!notifyer.expired()) {
+                         notifyer.lock()->DoResume();
+                     }
+                 }
              }
          });
 }
diff --git a/server/robotserver/coroutine.h b/server/robotserver/coroutine.h
index 6cc9dc2e..a9a8d74e 100644
--- a/server/robotserver/coroutine.h
+++ b/server/robotserver/coroutine.h
@@ -32,11 +32,12 @@ class Awaiter : public std::enable_shared_from_this<Awaiter>
         return done_;
     }
 
+    virtual void DoResume() {};
+
 protected:
     std::list<std::weak_ptr<Awaiter>> notifyers_;
     void Await(std::shared_ptr<Awaiter> notifyer);
     virtual void DoAwait() = 0;
-    virtual void DoResume() {};
 
  private:
     bool done_ = false;