diff --git a/health/2.0/default/Health.cpp b/health/2.0/default/Health.cpp
index e02bfa9..4a4bee0 100644
--- a/health/2.0/default/Health.cpp
+++ b/health/2.0/default/Health.cpp
@@ -46,7 +46,7 @@
     }
 
     {
-        std::lock_guard<std::mutex> _lock(callbacks_lock_);
+        std::lock_guard<decltype(callbacks_lock_)> lock(callbacks_lock_);
         callbacks_.push_back(callback);
         // unlock
     }
@@ -65,7 +65,7 @@
     if (callback == nullptr) return false;
 
     bool removed = false;
-    std::lock_guard<std::mutex> _lock(callbacks_lock_);
+    std::lock_guard<decltype(callbacks_lock_)> lock(callbacks_lock_);
     for (auto it = callbacks_.begin(); it != callbacks_.end();) {
         if (interfacesEqual(*it, callback)) {
             it = callbacks_.erase(it);
@@ -175,7 +175,7 @@
     healthInfo->diskStats = stats;
     healthInfo->storageInfos = info;
 
-    std::lock_guard<std::mutex> _lock(callbacks_lock_);
+    std::lock_guard<decltype(callbacks_lock_)> lock(callbacks_lock_);
     for (auto it = callbacks_.begin(); it != callbacks_.end();) {
         auto ret = (*it)->healthInfoChanged(*healthInfo);
         if (!ret.isOk() && ret.isDeadObject()) {