diff --git a/apps/emqx_sn/examples/simple_example2.erl b/apps/emqx_sn/examples/simple_example2.erl
index b9ada6d22..9af9262e9 100644
--- a/apps/emqx_sn/examples/simple_example2.erl
+++ b/apps/emqx_sn/examples/simple_example2.erl
@@ -6,6 +6,7 @@
 -define(PORT, 1884).
 
 -export([start/0]).
+-export([gen_register_packet/2]).
 
 start() ->
     io:format("start to connect ~p:~p~n", [?HOST, ?PORT]),
diff --git a/apps/emqx_sn/examples/simple_example3.erl b/apps/emqx_sn/examples/simple_example3.erl
index 40f0bf572..6bc41f1e8 100644
--- a/apps/emqx_sn/examples/simple_example3.erl
+++ b/apps/emqx_sn/examples/simple_example3.erl
@@ -6,6 +6,7 @@
 -define(PORT, 1884).
 
 -export([start/0]).
+-export([gen_register_packet/2]).
 
 start() ->
     io:format("start to connect ~p:~p~n", [?HOST, ?PORT]),
diff --git a/apps/emqx_sn/examples/simple_example4.erl b/apps/emqx_sn/examples/simple_example4.erl
index 6beb5835c..1b4809626 100644
--- a/apps/emqx_sn/examples/simple_example4.erl
+++ b/apps/emqx_sn/examples/simple_example4.erl
@@ -5,7 +5,7 @@
 -define(HOST, {127,0,0,1}).
 -define(PORT, 1884).
 
--export([start/0]).
+-export([start/1]).
 
 start(LoopTimes) ->
     io:format("start to connect ~p:~p~n", [?HOST, ?PORT]),
diff --git a/test/emqx_broker_sup_SUITE.erl b/test/emqx_broker_sup_SUITE.erl
index 04881f308..20bcfbbf6 100644
--- a/test/emqx_broker_sup_SUITE.erl
+++ b/test/emqx_broker_sup_SUITE.erl
@@ -61,5 +61,5 @@ t_restart_shared_sub(Config) when is_list(Config) ->
        after 2000 ->
                  false
        end);
-t_restart_shared_sub({'end', Config}) ->
+t_restart_shared_sub({'end', _Config}) ->
     emqx:unsubscribe(<<"$share/grpa/t/a">>).