diff --git a/libraries/chain/controller.cpp b/libraries/chain/controller.cpp
index eb60ec697d..7a35b8a772 100644
--- a/libraries/chain/controller.cpp
+++ b/libraries/chain/controller.cpp
@@ -953,7 +953,7 @@ struct controller_impl {
    const chain_id_type             chain_id; // read by thread_pool threads, value will not be changed
    bool                            replaying = false;
    bool                            is_producer_node = false; // true if node is configured as a block producer
-   db_read_mode                    read_mode = db_read_mode::HEAD;
+   const db_read_mode              read_mode;
    bool                            in_trx_requiring_checks = false; ///< if true, checks that are normally skipped on replay (e.g. auth checks) cannot be skipped
    std::optional<fc::microseconds> subjective_cpu_leeway;
    bool                            trusted_producer_light_validation = false;
diff --git a/libraries/chain/include/eosio/chain/controller.hpp b/libraries/chain/include/eosio/chain/controller.hpp
index 599800e753..73973b82fa 100644
--- a/libraries/chain/include/eosio/chain/controller.hpp
+++ b/libraries/chain/include/eosio/chain/controller.hpp
@@ -394,8 +394,10 @@ namespace eosio::chain {
 
          chain_id_type get_chain_id()const;
 
+         // thread safe
          db_read_mode get_read_mode()const;
          validation_mode get_validation_mode()const;
+
          /// @return true if terminate-at-block reached
          /// not-thread-safe
          bool should_terminate() const;