diff --git a/apps/emqx_conf/src/emqx_conf_schema.erl b/apps/emqx_conf/src/emqx_conf_schema.erl
index cfcc12905..350ee9e3a 100644
--- a/apps/emqx_conf/src/emqx_conf_schema.erl
+++ b/apps/emqx_conf/src/emqx_conf_schema.erl
@@ -741,22 +741,10 @@ sort_log_levels(Levels) ->
 %% utils
 -spec(conf_get(string() | [string()], hocon:config()) -> term()).
 conf_get(Key, Conf) ->
-    V = hocon_schema:get_value(Key, Conf),
-    case is_binary(V) of
-        true ->
-            binary_to_list(V);
-        false ->
-            V
-    end.
+    ensure_list(hocon_schema:get_value(Key, Conf)).
 
 conf_get(Key, Conf, Default) ->
-    V = hocon_schema:get_value(Key, Conf, Default),
-    case is_binary(V) of
-        true ->
-            binary_to_list(V);
-        false ->
-            V
-    end.
+    ensure_list(hocon_schema:get_value(Key, Conf, Default)).
 
 filter(Opts) ->
     [{K, V} || {K, V} <- Opts, V =/= undefined].
@@ -812,5 +800,14 @@ to_atom(Str) when is_list(Str) ->
 to_atom(Bin) when is_binary(Bin) ->
     binary_to_atom(Bin, utf8).
 
+-spec ensure_list(binary() | list(char())) -> list(char()).
+ensure_list(V) ->
+    case is_binary(V) of
+        true ->
+            binary_to_list(V);
+        false ->
+            V
+    end.
+
 roots(Module) ->
     lists:map(fun({_BinName, Root}) -> Root end, hocon_schema:roots(Module)).