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authorJosé Valim <[email protected]>2017-05-10 14:20:13 +0200
committerJosé Valim <[email protected]>2017-05-15 16:27:39 +0200
commit7ff352ef8a5393a017ce493ba1a1fc3be54be245 (patch)
tree4623c2cbe6a4f25b9983f011a30be621bcc8fa5c /lib/stdlib/src/gen_server.erl
parent8baada6ba97f7809c99cae4e799fddb273a54882 (diff)
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Do not discard stacktraces on gen_server exits
Prior to this patch, the stacktrace of an error or exit in a callback would always be discarded in crash reports. For example, an exit(crashed) in handle_call/3 would emit: =CRASH REPORT==== 10-May-2017::14:15:50 === crasher: initial call: gen_server_SUITE:init/1 pid: <0.201.0> registered_name: [] exception exit: crashed in function gen_server:terminate/8 (src/gen_server.erl, line 828) Note that the stacktrace is pointing to the gen_server internal terminate implementation that calls exit/1. This patch uses erlang:raise/3 so the stacktrace is not lost, allowing proc_lib to show the class, reason and stacktrace coming from the user implementation (in this case gen_server_SUITE): =CRASH REPORT==== 10-May-2017::14:16:44 === crasher: initial call: gen_server_SUITE:init/1 pid: <0.197.0> registered_name: [] exception exit: crashed in function gen_server_SUITE:handle_call/3 (gen_server_SUITE.erl, line 1529) This change is completely backwards compatible as using erlang:raise/3 will still emit the same exit reason to any linked process and monitor as before.
Diffstat (limited to 'lib/stdlib/src/gen_server.erl')
-rw-r--r--lib/stdlib/src/gen_server.erl174
1 files changed, 96 insertions, 78 deletions
diff --git a/lib/stdlib/src/gen_server.erl b/lib/stdlib/src/gen_server.erl
index ba0a7ae8e5..4e9dea8e5a 100644
--- a/lib/stdlib/src/gen_server.erl
+++ b/lib/stdlib/src/gen_server.erl
@@ -109,6 +109,10 @@
-import(error_logger, [format/2]).
+-define(
+ STACKTRACE(),
+ try throw(ok) catch _ -> erlang:get_stacktrace() end).
+
%%%=========================================================================
%%% API
%%%=========================================================================
@@ -326,15 +330,16 @@ init_it(Starter, self, Name, Mod, Args, Options) ->
init_it(Starter, Parent, Name0, Mod, Args, Options) ->
Name = gen:name(Name0),
Debug = gen:debug_options(Name, Options),
- HibernateAfterTimeout = gen:hibernate_after(Options),
- case catch Mod:init(Args) of
- {ok, State} ->
+ HibernateAfterTimeout = gen:hibernate_after(Options),
+
+ case init_it(Mod, Args) of
+ {ok, {ok, State}} ->
proc_lib:init_ack(Starter, {ok, self()}),
loop(Parent, Name, State, Mod, infinity, HibernateAfterTimeout, Debug);
- {ok, State, Timeout} ->
+ {ok, {ok, State, Timeout}} ->
proc_lib:init_ack(Starter, {ok, self()}),
loop(Parent, Name, State, Mod, Timeout, HibernateAfterTimeout, Debug);
- {stop, Reason} ->
+ {ok, {stop, Reason}} ->
%% For consistency, we must make sure that the
%% registered name (if any) is unregistered before
%% the parent process is notified about the failure.
@@ -344,18 +349,25 @@ init_it(Starter, Parent, Name0, Mod, Args, Options) ->
gen:unregister_name(Name0),
proc_lib:init_ack(Starter, {error, Reason}),
exit(Reason);
- ignore ->
+ {ok, ignore} ->
gen:unregister_name(Name0),
proc_lib:init_ack(Starter, ignore),
exit(normal);
- {'EXIT', Reason} ->
- gen:unregister_name(Name0),
- proc_lib:init_ack(Starter, {error, Reason}),
- exit(Reason);
- Else ->
+ {ok, Else} ->
Error = {bad_return_value, Else},
proc_lib:init_ack(Starter, {error, Error}),
- exit(Error)
+ exit(Error);
+ {'EXIT', Class, Reason, Stacktrace} ->
+ gen:unregister_name(Name0),
+ proc_lib:init_ack(Starter, {error, terminate_reason(Class, Reason, Stacktrace)}),
+ erlang:raise(Class, Reason, Stacktrace)
+ end.
+init_it(Mod, Args) ->
+ try
+ {ok, Mod:init(Args)}
+ catch
+ throw:R -> {ok, R};
+ Class:R -> {'EXIT', Class, R, erlang:get_stacktrace()}
end.
%%%========================================================================
@@ -397,7 +409,7 @@ decode_msg(Msg, Parent, Name, State, Mod, Time, HibernateAfterTimeout, Debug, Hi
sys:handle_system_msg(Req, From, Parent, ?MODULE, Debug,
[Name, State, Mod, Time, HibernateAfterTimeout], Hib);
{'EXIT', Parent, Reason} ->
- terminate(Reason, Name, undefined, Msg, Mod, State, Debug);
+ terminate(Reason, ?STACKTRACE(), Name, undefined, Msg, Mod, State, Debug);
_Msg when Debug =:= [] ->
handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout);
_Msg ->
@@ -589,17 +601,11 @@ start_monitor(Node, Name) when is_atom(Node), is_atom(Name) ->
%% ---------------------------------------------------
%% Helper functions for try-catch of callbacks.
%% Returns the return value of the callback, or
-%% {'EXIT', ExitReason, ReportReason} (if an exception occurs)
+%% {'EXIT', Class, Reason, Stack} (if an exception occurs)
%%
-%% ExitReason is the reason that shall be used when the process
-%% terminates.
-%%
-%% ReportReason is the reason that shall be printed in the error
-%% report.
-%%
-%% These functions are introduced in order to add the stack trace in
-%% the error report produced when a callback is terminated with
-%% erlang:exit/1 (OTP-12263).
+%% The Class, Reason and Stack are given to erlang:raise/3
+%% to make sure proc_lib receives the proper reasons and
+%% stacktraces.
%% ---------------------------------------------------
try_dispatch({'$gen_cast', Msg}, Mod, State) ->
@@ -621,15 +627,10 @@ try_dispatch(Mod, Func, Msg, State) ->
[Mod, Msg]),
{ok, {noreply, State}};
true ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', {R, Stacktrace}, {R, Stacktrace}}
+ {'EXIT', error, R, erlang:get_stacktrace()}
end;
- error:R ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', {R, Stacktrace}, {R, Stacktrace}};
- exit:R ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', R, {R, Stacktrace}}
+ Class:R ->
+ {'EXIT', Class, R, erlang:get_stacktrace()}
end.
try_handle_call(Mod, Msg, From, State) ->
@@ -638,12 +639,8 @@ try_handle_call(Mod, Msg, From, State) ->
catch
throw:R ->
{ok, R};
- error:R ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', {R, Stacktrace}, {R, Stacktrace}};
- exit:R ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', R, {R, Stacktrace}}
+ Class:R ->
+ {'EXIT', Class, R, erlang:get_stacktrace()}
end.
try_terminate(Mod, Reason, State) ->
@@ -654,12 +651,8 @@ try_terminate(Mod, Reason, State) ->
catch
throw:R ->
{ok, R};
- error:R ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', {R, Stacktrace}, {R, Stacktrace}};
- exit:R ->
- Stacktrace = erlang:get_stacktrace(),
- {'EXIT', R, {R, Stacktrace}}
+ Class:R ->
+ {'EXIT', Class, R, erlang:get_stacktrace()}
end;
false ->
{ok, ok}
@@ -684,10 +677,11 @@ handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, HibernateAfterTim
{ok, {noreply, NState, Time1}} ->
loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []);
{ok, {stop, Reason, Reply, NState}} ->
- {'EXIT', R} =
- (catch terminate(Reason, Name, From, Msg, Mod, NState, [])),
- reply(From, Reply),
- exit(R);
+ try
+ terminate(Reason, ?STACKTRACE(), Name, From, Msg, Mod, NState, [])
+ after
+ reply(From, Reply)
+ end;
Other -> handle_common_reply(Other, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State)
end;
handle_msg(Msg, Parent, Name, State, Mod, HibernateAfterTimeout) ->
@@ -712,10 +706,11 @@ handle_msg({'$gen_call', From, Msg}, Parent, Name, State, Mod, HibernateAfterTim
{noreply, NState}),
loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1);
{ok, {stop, Reason, Reply, NState}} ->
- {'EXIT', R} =
- (catch terminate(Reason, Name, From, Msg, Mod, NState, Debug)),
- _ = reply(Name, From, Reply, NState, Debug),
- exit(R);
+ try
+ terminate(Reason, ?STACKTRACE(), Name, From, Msg, Mod, NState, Debug)
+ after
+ _ = reply(Name, From, Reply, NState, Debug)
+ end;
Other ->
handle_common_reply(Other, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State, Debug)
end;
@@ -730,11 +725,11 @@ handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout,
{ok, {noreply, NState, Time1}} ->
loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, []);
{ok, {stop, Reason, NState}} ->
- terminate(Reason, Name, From, Msg, Mod, NState, []);
- {'EXIT', ExitReason, ReportReason} ->
- terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, []);
+ terminate(Reason, ?STACKTRACE(), Name, From, Msg, Mod, NState, []);
+ {'EXIT', Class, Reason, Stacktrace} ->
+ terminate(Class, Reason, Stacktrace, Name, From, Msg, Mod, State, []);
{ok, BadReply} ->
- terminate({bad_return_value, BadReply}, Name, From, Msg, Mod, State, [])
+ terminate({bad_return_value, BadReply}, ?STACKTRACE(), Name, From, Msg, Mod, State, [])
end.
handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout, State, Debug) ->
@@ -748,11 +743,11 @@ handle_common_reply(Reply, Parent, Name, From, Msg, Mod, HibernateAfterTimeout,
{noreply, NState}),
loop(Parent, Name, NState, Mod, Time1, HibernateAfterTimeout, Debug1);
{ok, {stop, Reason, NState}} ->
- terminate(Reason, Name, From, Msg, Mod, NState, Debug);
- {'EXIT', ExitReason, ReportReason} ->
- terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, Debug);
+ terminate(Reason, ?STACKTRACE(), Name, From, Msg, Mod, NState, Debug);
+ {'EXIT', Class, Reason, Stacktrace} ->
+ terminate(Class, Reason, Stacktrace, Name, From, Msg, Mod, State, Debug);
{ok, BadReply} ->
- terminate({bad_return_value, BadReply}, Name, From, Msg, Mod, State, Debug)
+ terminate({bad_return_value, BadReply}, ?STACKTRACE(), Name, From, Msg, Mod, State, Debug)
end.
reply(Name, {To, Tag}, Reply, State, Debug) ->
@@ -770,7 +765,7 @@ system_continue(Parent, Debug, [Name, State, Mod, Time, HibernateAfterTimeout])
-spec system_terminate(_, _, _, [_]) -> no_return().
system_terminate(Reason, _Parent, Debug, [Name, State, Mod, _Time, _HibernateAfterTimeout]) ->
- terminate(Reason, Name, undefined, [], Mod, State, Debug).
+ terminate(Reason, ?STACKTRACE(), Name, undefined, [], Mod, State, Debug).
system_code_change([Name, State, Mod, Time, HibernateAfterTimeout], _Module, OldVsn, Extra) ->
case catch Mod:code_change(OldVsn, State, Extra) of
@@ -811,35 +806,58 @@ print_event(Dev, Event, Name) ->
%%% ---------------------------------------------------
%%% Terminate the server.
+%%%
+%%% terminate/8 is triggered by {stop, Reason} or bad
+%%% return values. The stacktrace is generated via the
+%%% ?STACKTRACE() macro and the ReportReason must not
+%%% be wrapped in tuples.
+%%%
+%%% terminate/9 is triggered in case of error/exit in
+%%% the user callback. In this case the report reason
+%%% always includes the user stacktrace.
+%%%
+%%% The reason received in the terminate/2 callbacks
+%%% always includes the stacktrace for errors and never
+%%% for exits.
%%% ---------------------------------------------------
-
--spec terminate(_, _, _, _, _, _, _) -> no_return().
-terminate(Reason, Name, From, Msg, Mod, State, Debug) ->
- terminate(Reason, Reason, Name, From, Msg, Mod, State, Debug).
-spec terminate(_, _, _, _, _, _, _, _) -> no_return().
-terminate(ExitReason, ReportReason, Name, From, Msg, Mod, State, Debug) ->
- Reply = try_terminate(Mod, ExitReason, State),
+terminate(Reason, Stacktrace, Name, From, Msg, Mod, State, Debug) ->
+ terminate(exit, Reason, Stacktrace, Reason, Name, From, Msg, Mod, State, Debug).
+
+-spec terminate(_, _, _, _, _, _, _, _, _) -> no_return().
+terminate(Class, Reason, Stacktrace, Name, From, Msg, Mod, State, Debug) ->
+ ReportReason = {Reason, Stacktrace},
+ terminate(Class, Reason, Stacktrace, ReportReason, Name, From, Msg, Mod, State, Debug).
+
+-spec terminate(_, _, _, _, _, _, _, _, _, _) -> no_return().
+terminate(Class, Reason, Stacktrace, ReportReason, Name, From, Msg, Mod, State, Debug) ->
+ Reply = try_terminate(Mod, terminate_reason(Class, Reason, Stacktrace), State),
case Reply of
- {'EXIT', ExitReason1, ReportReason1} ->
+ {'EXIT', C, R, S} ->
FmtState = format_status(terminate, Mod, get(), State),
- error_info(ReportReason1, Name, From, Msg, FmtState, Debug),
- exit(ExitReason1);
+ error_info({R, S}, Name, From, Msg, FmtState, Debug),
+ erlang:raise(C, R, S);
_ ->
- case ExitReason of
- normal ->
- exit(normal);
- shutdown ->
- exit(shutdown);
- {shutdown,_}=Shutdown ->
- exit(Shutdown);
+ case {Class, Reason} of
+ {exit, normal} -> ok;
+ {exit, shutdown} -> ok;
+ {exit, {shutdown,_}} -> ok;
_ ->
FmtState = format_status(terminate, Mod, get(), State),
- error_info(ReportReason, Name, From, Msg, FmtState, Debug),
- exit(ExitReason)
+ error_info(ReportReason, Name, From, Msg, FmtState, Debug)
end
+ end,
+ case Stacktrace of
+ [] ->
+ erlang:Class(Reason);
+ _ ->
+ erlang:raise(Class, Reason, Stacktrace)
end.
+terminate_reason(error, Reason, Stacktrace) -> {Reason, Stacktrace};
+terminate_reason(exit, Reason, _Stacktrace) -> Reason.
+
error_info(_Reason, application_controller, _From, _Msg, _State, _Debug) ->
%% OTP-5811 Don't send an error report if it's the system process
%% application_controller which is terminating - let init take care