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authorDan Gudmundsson <[email protected]>2014-02-18 17:21:55 +0100
committerDan Gudmundsson <[email protected]>2014-02-19 15:32:19 +0100
commit397e69fa95457f9660831ba1e551c784eb61e93e (patch)
tree4a77b0bc80de8adfd3ec9e70b08c276220cafacb /lib/kernel/src
parent6c9002f9174d40b69b3a5bcd5ef219ce4ceb3622 (diff)
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kernel: Fix an application terminate deadlock possibility
Could happen if get_child was called during terminate. io (since it is a group_leader) also causes problems after get_child was called. Split up and do it async.
Diffstat (limited to 'lib/kernel/src')
-rw-r--r--lib/kernel/src/application_master.erl38
1 files changed, 23 insertions, 15 deletions
diff --git a/lib/kernel/src/application_master.erl b/lib/kernel/src/application_master.erl
index 68f78c6eb8..bc15b5a7de 100644
--- a/lib/kernel/src/application_master.erl
+++ b/lib/kernel/src/application_master.erl
@@ -1,7 +1,7 @@
%%
%% %CopyrightBegin%
%%
-%% Copyright Ericsson AB 1996-2013. All Rights Reserved.
+%% Copyright Ericsson AB 1996-2014. All Rights Reserved.
%%
%% The contents of this file are subject to the Erlang Public License,
%% Version 1.1, (the "License"); you may not use this file except in
@@ -27,7 +27,7 @@
-include("application_master.hrl").
--record(state, {child, appl_data, children = [], procs = 0, gleader}).
+-record(state, {child, appl_data, children = [], procs = 0, gleader, req=[]}).
%%-----------------------------------------------------------------
%% Func: start_link/1
@@ -205,22 +205,25 @@ terminate_loop(Child, State) ->
%%-----------------------------------------------------------------
%% The Application Master is linked to *all* processes in the group
-%% (application).
+%% (application).
%%-----------------------------------------------------------------
handle_msg({get_child, Tag, From}, State) ->
- From ! {Tag, get_child_i(State#state.child)},
- State;
+ get_child_i(State, Tag, From);
handle_msg({stop, Tag, From}, State) ->
catch terminate(normal, State),
From ! {Tag, ok},
exit(normal);
+handle_msg({child, Ref, GrandChild, Mod}, #state{req=Reqs0}=State) ->
+ {value, {_, Tag, From}, Reqs} = lists:keytake(Ref, 1, Reqs0),
+ From ! {Tag, {GrandChild, Mod}},
+ State#state{req=Reqs};
handle_msg(_, State) ->
State.
-
-terminate(Reason, State) ->
- terminate_child(State#state.child, State),
- kill_children(State#state.children),
+terminate(Reason, State = #state{child=Child, children=Children, req=Reqs}) ->
+ _ = [From ! {Tag, error} || {_, Tag, From} <- Reqs],
+ terminate_child(Child, State),
+ kill_children(Children),
exit(Reason).
@@ -342,8 +345,8 @@ start_supervisor(Type, M, A) ->
loop_it(Parent, Child, Mod, AppState) ->
receive
- {Parent, get_child} ->
- Parent ! {self(), Child, Mod},
+ {Parent, get_child, Ref} ->
+ Parent ! {child, Ref, Child, Mod},
loop_it(Parent, Child, Mod, AppState);
{Parent, terminate} ->
NewAppState = prep_stop(Mod, AppState),
@@ -382,10 +385,15 @@ prep_stop(Mod, AppState) ->
NewAppState
end.
-get_child_i(Child) ->
- Child ! {self(), get_child},
- receive
- {Child, GrandChild, Mod} -> {GrandChild, Mod}
+get_child_i(#state{child=Child, req=Reqs}=State, Tag, From) ->
+ Ref = erlang:make_ref(),
+ case erlang:is_process_alive(Child) of
+ true ->
+ Child ! {self(), get_child, Ref},
+ State#state{req=[{Ref, Tag, From}|Reqs]};
+ false ->
+ From ! {Tag, error},
+ State
end.
terminate_child_i(Child, State) ->