diff --git a/apps/emqx_lua_hook/src/emqx_lua_hook.erl b/apps/emqx_lua_hook/src/emqx_lua_hook.erl
index ad6507521..ab26e94c0 100644
--- a/apps/emqx_lua_hook/src/emqx_lua_hook.erl
+++ b/apps/emqx_lua_hook/src/emqx_lua_hook.erl
@@ -196,4 +196,4 @@ do_unloadall(Scripts) ->
     ok.
 
 do_unload(Script) ->
-    emqx_lua_script:unregister_hooks(Script).
+    emqx_lua_script:unregister_hooks(Script), ok.
diff --git a/apps/emqx_management/src/emqx_mgmt_auth.erl b/apps/emqx_management/src/emqx_mgmt_auth.erl
index f33eea453..0abb2f43a 100644
--- a/apps/emqx_management/src/emqx_mgmt_auth.erl
+++ b/apps/emqx_management/src/emqx_mgmt_auth.erl
@@ -85,7 +85,7 @@ add_app(AppId, Name) when is_binary(AppId) ->
 add_app(AppId, Name, Desc, Status, Expired) when is_binary(AppId) ->
     add_app(AppId, Name, undefined, Desc, Status, Expired).
 
--spec(add_app(appid(), binary(), binary(), binary(), boolean(), integer() | undefined)
+-spec(add_app(appid(), binary(), binary() | undefined, binary(), boolean(), integer() | undefined)
       -> {ok, appsecret()}
        | {error, term()}).
 add_app(AppId, Name, Secret, Desc, Status, Expired) when is_binary(AppId) ->
@@ -99,11 +99,11 @@ add_app(AppId, Name, Secret, Desc, Status, Expired) when is_binary(AppId) ->
     AddFun = fun() ->
                  case mnesia:wread({mqtt_app, AppId}) of
                      [] -> mnesia:write(App);
-                     _  -> mnesia:abort(alread_existed)
+                     _  -> mnesia:abort(alread_existed), ok
                  end
              end,
     case mnesia:transaction(AddFun) of
-        {atomic, ok} -> {ok, Secret1};
+        {atomic, _} -> {ok, Secret1};
         {aborted, Reason} -> {error, Reason}
     end.
 
@@ -138,7 +138,7 @@ get_appsecret(AppId) when is_binary(AppId) ->
         [] -> undefined
     end.
 
--spec(lookup_app(appid()) -> {{appid(), appsecret(), binary(), binary(), boolean(), integer() | undefined} | undefined}).
+-spec(lookup_app(appid()) -> undefined | {appid(), appsecret(), binary(), binary(), boolean(), integer() | undefined}).
 lookup_app(AppId) when is_binary(AppId) ->
     case mnesia:dirty_read(mqtt_app, AppId) of
         [#mqtt_app{id = AppId,
diff --git a/apps/emqx_management/src/emqx_mgmt_cli.erl b/apps/emqx_management/src/emqx_mgmt_cli.erl
index b56af8b78..8a9f57f67 100644
--- a/apps/emqx_management/src/emqx_mgmt_cli.erl
+++ b/apps/emqx_management/src/emqx_mgmt_cli.erl
@@ -420,7 +420,7 @@ log(["primary-level", Level]) ->
     emqx_ctl:print("~s~n", [emqx_logger:get_primary_log_level()]);
 
 log(["handlers", "list"]) ->
-    [emqx_ctl:print("LogHandler(id=~s, level=~s, destination=~s, status=~s)~n", [Id, Level, Dst, Status])
+    _ = [emqx_ctl:print("LogHandler(id=~s, level=~s, destination=~s, status=~s)~n", [Id, Level, Dst, Status])
         || #{id := Id, level := Level, dst := Dst, status := Status} <- emqx_logger:get_log_handlers()],
     ok;
 
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine.erl b/apps/emqx_rule_engine/src/emqx_rule_engine.erl
index a2c81d92d..a374c822b 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine.erl
@@ -250,7 +250,7 @@ update_resource(#{id := Id, type := Type, config := NewConfig, description := De
         {ok, #resource_type{on_create = {Module, Create},
                             params_spec = ParamSpec}} ->
             Config = emqx_rule_validator:validate_params(NewConfig, ParamSpec),
-            delete_resource(Id),
+            _ = delete_resource(Id),
             emqx_rule_registry:add_resource(#resource{id = Id,
                                                       config = Config,
                                                       type = Type,
@@ -626,4 +626,4 @@ start_reinitial_loop(Id) ->
                 start_resource(Id);
            not_found -> ok
         end
-    end).
\ No newline at end of file
+    end).
diff --git a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
index d3f427723..aafaf0082 100644
--- a/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
+++ b/apps/emqx_rule_engine/src/emqx_rule_engine_api.erl
@@ -326,7 +326,7 @@ update_resource(#{id := Id}, Params) ->
         {ok, #resource{id = Id, type = Type} = _OldResource} ->
                Config = maps:get(config, parse_resource_params(Params)),
                Description = maps:get(description, parse_resource_params(Params)),
-               emqx_rule_engine:update_resource(#{id => Id,
+               _ = emqx_rule_engine:update_resource(#{id => Id,
                                                   config => Config,
                                                   type => Type,
                                                   description => Description,