diff --git a/cmds/installd/InstalldNativeService.h b/cmds/installd/InstalldNativeService.h
index 5397a74..ec81462 100644
--- a/cmds/installd/InstalldNativeService.h
+++ b/cmds/installd/InstalldNativeService.h
@@ -99,6 +99,9 @@
             const std::string& outputPath);
     binder::Status deleteOdex(const std::string& apkPath, const std::string& instructionSet,
             const std::string& outputPath);
+
+private:
+    std::recursive_mutex mLock;
 };
 
 }  // namespace installd