diff --git a/power_manager/powerd/system/dbus_wrapper_stub.cc b/power_manager/powerd/system/dbus_wrapper_stub.cc
index 24c577a..430d7c5 100644
--- a/power_manager/powerd/system/dbus_wrapper_stub.cc
+++ b/power_manager/powerd/system/dbus_wrapper_stub.cc
@@ -149,7 +149,7 @@
   if (it == service_availability_callbacks_.end())
     return;
 
-  for (auto cb : it->second)
+  for (auto& cb : it->second)
     std::move(cb).Run(available);
   service_availability_callbacks_.erase(it);
 }