diff --git a/extend/lualog/lualog/lualog.cpp b/extend/lualog/lualog/lualog.cpp
index 001b93b0..6a2a68c1 100644
--- a/extend/lualog/lualog/lualog.cpp
+++ b/extend/lualog/lualog/lualog.cpp
@@ -43,7 +43,7 @@ namespace logger {
     }
 
     template<size_t... integers>
-    int tformat(lua_State* L, log_level lvl, cstring& tag, cstring& feature, int flag, cstring& vfmt, std::index_sequence<integers...>&&) {
+    int tformat(lua_State* L, log_level lvl, cstring& tag, cstring& feature, int flag, vstring vfmt, std::index_sequence<integers...>&&) {
         try {
             auto msg = fmt::format(vfmt, read_args(L, flag, integers + 6)...);
             return zformat(L, lvl, tag, feature, msg);
@@ -71,10 +71,10 @@ namespace logger {
             size_t flag = lua_tointeger(L, 2);
             sstring tag = lua_to_native<sstring>(L, 3);
             sstring feature = lua_to_native<sstring>(L, 4);
-            sstring vfmt = lua_to_native<sstring>(L, 5);
+            vstring vfmt = lua_to_native<vstring>(L, 5);
             int arg_num = lua_gettop(L) - 5;
             switch (arg_num) {
-            case 0: return zformat(L, lvl, tag, feature, vfmt);
+            case 0: return zformat(L, lvl, tag, feature, string(vfmt.data(), vfmt.size()));
             case 1: return tformat(L, lvl, tag, feature, flag, vfmt, make_index_sequence<1>{});
             case 2: return tformat(L, lvl, tag, feature, flag, vfmt, make_index_sequence<2>{});
             case 3: return tformat(L, lvl, tag, feature, flag, vfmt, make_index_sequence<3>{});