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author | Björn Gustavsson <bjorn@erlang.org> | 2016-04-29 15:50:19 +0200 |
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committer | Björn Gustavsson <bjorn@erlang.org> | 2016-05-04 10:21:30 +0200 |
commit | f8e4ac533d388b39d5980092e5dd7a9d4ffee60b (patch) | |
tree | 87552c7a77d2dcefdf30dbb65bdfee0041b13628 /lib | |
parent | eb7c5e3fa1f2d2bac21c4714b3a627a5517f797d (diff) | |
download | otp-f8e4ac533d388b39d5980092e5dd7a9d4ffee60b.tar.gz otp-f8e4ac533d388b39d5980092e5dd7a9d4ffee60b.tar.bz2 otp-f8e4ac533d388b39d5980092e5dd7a9d4ffee60b.zip |
Avoid deadlock when an on_load function makes an external call to the module itself
Diffstat (limited to 'lib')
-rw-r--r-- | lib/kernel/src/code_server.erl | 35 | ||||
-rw-r--r-- | lib/kernel/test/code_SUITE.erl | 30 |
2 files changed, 50 insertions, 15 deletions
diff --git a/lib/kernel/src/code_server.erl b/lib/kernel/src/code_server.erl index 356c6630fa..10264382eb 100644 --- a/lib/kernel/src/code_server.erl +++ b/lib/kernel/src/code_server.erl @@ -32,7 +32,8 @@ -import(lists, [foreach/2]). --type on_load_item() :: {reference(),module(),file:name_all(),[pid()]}. +-type on_load_item() :: {{pid(),reference()},module(), + file:name_all(),[pid()]}. -record(state, {supervisor :: pid(), root :: file:name_all(), @@ -155,8 +156,8 @@ loop(#state{supervisor=Supervisor}=State0) -> system_terminate(Reason, Supervisor, [], State0); {system, From, Msg} -> handle_system_msg(running,Msg, From, Supervisor, State0); - {'DOWN',Ref,process,_,Res} -> - State = finish_on_load(Ref, Res, State0), + {'DOWN',Ref,process,Pid,Res} -> + State = finish_on_load({Pid,Ref}, Res, State0), loop(State); _Msg -> loop(State0) @@ -1312,38 +1313,46 @@ handle_on_load(Mod, File, From, #state{on_load=OnLoad0}=St0) -> Res = erlang:call_on_load_function(Mod), exit(Res) end, - {_,Ref} = spawn_monitor(Fun), - OnLoad = [{Ref,Mod,File,[From]}|OnLoad0], + PidRef = spawn_monitor(Fun), + OnLoad = [{PidRef,Mod,File,[From]}|OnLoad0], St = St0#state{on_load=OnLoad}, {noreply,St}. pending_on_load(_, _, #state{on_load=[]}) -> no; pending_on_load(Mod, From, #state{on_load=OnLoad0}=St) -> - case lists:keymember(Mod, 2, OnLoad0) of + case lists:keyfind(Mod, 2, OnLoad0) of false -> no; - true -> + {{From,_Ref},Mod,_File,_Pids} -> + %% The on_load function tried to make an external + %% call to its own module. That would be a deadlock. + %% Fail the call. (The call is probably from error_handler, + %% and it will ignore the actual error reason and cause + %% an undef execption.) + _ = reply(From, {error,deadlock}), + {yes,St}; + {_,_,_,_} -> OnLoad = pending_on_load_1(Mod, From, OnLoad0), {yes,St#state{on_load=OnLoad}} end. -pending_on_load_1(Mod, From, [{Ref,Mod,File,Pids}|T]) -> - [{Ref,Mod,File,[From|Pids]}|T]; +pending_on_load_1(Mod, From, [{PidRef,Mod,File,Pids}|T]) -> + [{PidRef,Mod,File,[From|Pids]}|T]; pending_on_load_1(Mod, From, [H|T]) -> [H|pending_on_load_1(Mod, From, T)]; pending_on_load_1(_, _, []) -> []. -finish_on_load(Ref, OnLoadRes, #state{on_load=OnLoad0,moddb=Db}=State) -> - case lists:keyfind(Ref, 1, OnLoad0) of +finish_on_load(PidRef, OnLoadRes, #state{on_load=OnLoad0,moddb=Db}=State) -> + case lists:keyfind(PidRef, 1, OnLoad0) of false -> %% Since this process in general silently ignores messages %% it doesn't understand, it should also ignore a 'DOWN' %% message with an unknown reference. State; - {Ref,Mod,File,WaitingPids} -> + {PidRef,Mod,File,WaitingPids} -> finish_on_load_1(Mod, File, OnLoadRes, WaitingPids, Db), - OnLoad = [E || {R,_,_,_}=E <- OnLoad0, R =/= Ref], + OnLoad = [E || {R,_,_,_}=E <- OnLoad0, R =/= PidRef], State#state{on_load=OnLoad} end. diff --git a/lib/kernel/test/code_SUITE.erl b/lib/kernel/test/code_SUITE.erl index 547881f3b2..e238eea2de 100644 --- a/lib/kernel/test/code_SUITE.erl +++ b/lib/kernel/test/code_SUITE.erl @@ -35,7 +35,7 @@ purge_stacktrace/1, mult_lib_roots/1, bad_erl_libs/1, code_archive/1, code_archive2/1, on_load/1, on_load_binary/1, on_load_embedded/1, on_load_errors/1, on_load_update/1, - on_load_purge/1, + on_load_purge/1, on_load_self_call/1, big_boot_embedded/1, native_early_modules/1, get_mode/1, normalized_paths/1]). @@ -65,7 +65,7 @@ all() -> purge_stacktrace, mult_lib_roots, bad_erl_libs, code_archive, code_archive2, on_load, on_load_binary, on_load_embedded, on_load_errors, on_load_update, - on_load_purge, + on_load_purge, on_load_self_call, big_boot_embedded, native_early_modules, get_mode, normalized_paths]. groups() -> @@ -1523,6 +1523,32 @@ on_load_purge(_Config) -> end end. +on_load_self_call(_Config) -> + Mod = ?FUNCTION_NAME, + register(Mod, self()), + Tree = ?Q(["-module('@Mod@').\n", + "-export([ext/0]).\n", + "-on_load(f/0).\n", + "f() ->\n", + " '@Mod@' ! (catch '@Mod@':ext()),\n", + " ok.\n", + "ext() -> good_work.\n"]), + merl:print(Tree), + {ok,Mod,Code} = merl:compile(Tree), + + {'EXIT',{undef,_}} = on_load_do_load(Mod, Code), + good_work = on_load_do_load(Mod, Code), + + ok. + +on_load_do_load(Mod, Code) -> + spawn(fun() -> + {module,Mod} = code:load_binary(Mod, "", Code) + end), + receive + Any -> Any + end. + %% Test that the native code of early loaded modules is loaded. native_early_modules(Config) when is_list(Config) -> case erlang:system_info(hipe_architecture) of |