diff --git a/src/emqx_bridge.erl b/src/emqx_bridge.erl
index 6af56d11b..03e7a478e 100644
--- a/src/emqx_bridge.erl
+++ b/src/emqx_bridge.erl
@@ -323,10 +323,9 @@ connecting(enter, _, #{reconnect_delay_ms := Timeout,
         {ok, ConnRef, Conn} ->
             ?LOG(info, "[Bridge] Bridge ~p connected", [name()]),
             Action = {state_timeout, 0, connected},
-            {keep_state,
-             eval_bridge_handler(State#{ conn_ref => ConnRef
-                                       , connection => Conn}, connected),
-             Action};
+            State0 = State#{conn_ref => ConnRef, connection => Conn},
+            State1 = eval_bridge_handler(State0, connected),
+            {keep_state, State1, Action};
         error ->
             Action = {state_timeout, Timeout, reconnect},
             {keep_state_and_data, Action}
@@ -424,7 +423,7 @@ common(StateName, Type, Content, State) ->
 eval_bridge_handler(State = #{bridge_handler := ?NO_BRIDGE_HANDLER}, _Msg) ->
     State;
 eval_bridge_handler(State = #{bridge_handler := Handler}, Msg) ->
-    _ = Handler(Msg),
+    Handler(Msg),
     State.
 
 ensure_present(Key, Topic, State) ->
@@ -564,9 +563,8 @@ disconnect(#{connection := Conn,
              connect_module := Module
             } = State) when Conn =/= undefined ->
     ok = Module:stop(ConnRef, Conn),
-    eval_bridge_handler(State#{conn_ref => undefined,
-                               connection => undefined},
-                        disconnected);
+    State0 = State#{conn_ref => undefined, connection => undefined},
+    eval_bridge_handler(State0, disconnected);
 disconnect(State) ->
     eval_bridge_handler(State, disconnected).
 
diff --git a/src/emqx_client.erl b/src/emqx_client.erl
index 371b020f1..737c699ac 100644
--- a/src/emqx_client.erl
+++ b/src/emqx_client.erl
@@ -928,6 +928,11 @@ handle_event(info, {inet_reply, _Sock, {error, Reason}}, _, State) ->
     ?LOG(error, "[Client] Got tcp error: ~p", [Reason]),
     {stop, {shutdown, Reason}, State};
 
+handle_event(info, EventContent = {'EXIT', _Pid, normal}, StateName, _State) ->
+    ?LOG(error, "[Client] State: ~s, Unexpected Event: (info, ~p)",
+         [StateName, EventContent]),
+    keep_state_and_data;
+
 handle_event(EventType, EventContent, StateName, _StateData) ->
     ?LOG(error, "[Client] State: ~s, Unexpected Event: (~p, ~p)",
          [StateName, EventType, EventContent]),
diff --git a/src/emqx_session.erl b/src/emqx_session.erl
index 2ef64c9aa..f1aa6d3bd 100644
--- a/src/emqx_session.erl
+++ b/src/emqx_session.erl
@@ -676,6 +676,7 @@ terminate(Reason, #state{will_msg = WillMsg,
                          username = Username,
                          conn_pid = ConnPid,
                          old_conn_pid = OldConnPid}) ->
+    emqx_metrics:commit(),
     send_willmsg(WillMsg),
     [maybe_shutdown(Pid, Reason) || Pid <- [ConnPid, OldConnPid]],
     ok = emqx_hooks:run('session.terminated', [#{client_id => ClientId, username => Username}, Reason]).
diff --git a/src/emqx_tracer.erl b/src/emqx_tracer.erl
index 464a28ad2..c85aa5007 100644
--- a/src/emqx_tracer.erl
+++ b/src/emqx_tracer.erl
@@ -76,11 +76,21 @@ trace(publish, #message{from = From, topic = Topic, payload = Payload})
 %% @doc Start to trace client_id or topic.
 -spec(start_trace(trace_who(), logger:level(), string()) -> ok | {error, term()}).
 start_trace({client_id, ClientId}, Level, LogFile) ->
-    start_trace({start_trace, {client_id, ClientId}, Level, LogFile});
+    do_start_trace({client_id, ClientId}, Level, LogFile);
 start_trace({topic, Topic}, Level, LogFile) ->
-    start_trace({start_trace, {topic, Topic}, Level, LogFile}).
+    do_start_trace({topic, Topic}, Level, LogFile).
 
-start_trace(Req) -> gen_server:call(?MODULE, Req, infinity).
+do_start_trace(Who, Level, LogFile) ->
+    #{level := PrimaryLevel} = logger:get_primary_config(),
+    try logger:compare_levels(log_level(Level), PrimaryLevel) of
+        lt ->
+            {error, io_lib:format("Cannot trace at a log level (~s) lower than the primary log level (~s)", [Level, PrimaryLevel])};
+        _GtOrEq ->
+            gen_server:call(?MODULE, {start_trace, Who, Level, LogFile}, 5000)
+    catch
+        _:Error ->
+           {error, Error}
+    end.
 
 %% @doc Stop tracing client_id or topic.
 -spec(stop_trace(trace_who()) -> ok | {error, term()}).
@@ -109,7 +119,7 @@ handle_call({start_trace, Who, Level, LogFile}, _From, State = #state{traces = T
                                   config => #{type => halt, file => LogFile},
                                   filter_default => stop,
                                   filters => [{meta_key_filter,
-                                               {fun filter_by_meta_key/2, Who} }]}) of
+                                              {fun filter_by_meta_key/2, Who} }]}) of
         ok ->
             ?LOG(info, "[Tracer] Start trace for ~p", [Who]),
             {reply, ok, State#state{traces = maps:put(Who, {Level, LogFile}, Traces)}};
@@ -168,3 +178,14 @@ filter_by_meta_key(#{meta:=Meta}=LogEvent, {MetaKey, MetaValue}) ->
             end;
         _ -> ignore
     end.
+
+log_level(emergency) -> emergency;
+log_level(alert) -> alert;
+log_level(critical) -> critical;
+log_level(error) -> error;
+log_level(warning) -> warning;
+log_level(notice) -> notice;
+log_level(info) -> info;
+log_level(debug) -> debug;
+log_level(all) -> debug;
+log_level(_) -> throw(invalid_log_level).
diff --git a/test/emqx_tracer_SUITE.erl b/test/emqx_tracer_SUITE.erl
index 323700823..327930fc3 100644
--- a/test/emqx_tracer_SUITE.erl
+++ b/test/emqx_tracer_SUITE.erl
@@ -38,8 +38,12 @@ start_traces(_Config) ->
     emqx_client:connect(T),
 
     %% Start tracing
+    emqx_logger:set_log_level(error),
+    {error, _} = emqx_tracer:start_trace({client_id, <<"client">>}, debug, "tmp/client.log"),
+    emqx_logger:set_log_level(debug),
     ok = emqx_tracer:start_trace({client_id, <<"client">>}, debug, "tmp/client.log"),
     ok = emqx_tracer:start_trace({client_id, <<"client2">>}, all, "tmp/client2.log"),
+    {error, invalid_log_level} = emqx_tracer:start_trace({client_id, <<"client3">>}, bad_level, "tmp/client3.log"),
     ok = emqx_tracer:start_trace({topic, <<"a/#">>}, all, "tmp/topic_trace.log"),
     ct:sleep(100),