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authorJames Fish <[email protected]>2014-10-01 14:03:43 +0100
committerBjörn Gustavsson <[email protected]>2015-02-26 15:05:34 +0100
commit4a8f17aeccd950e4f76ea6ea6d9219a1e2c86df5 (patch)
treec10c8538c678af0cac99fbefaf7084e4ea794ba8 /lib/runtime_tools/src/dbg.erl
parentc9e36ab16034bb7fe71f772df6bba22070976bbf (diff)
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Ensure dbg tracer exits when dbg is stopped
Previously the tracer might receive an 'EXIT' message in the trace receive loop and treat it as garbage. Test uses a custom dbg process handler to reliably recreate the race condition, i.e. the message order {trace, ..}, {'EXIT, ..}.
Diffstat (limited to 'lib/runtime_tools/src/dbg.erl')
-rw-r--r--lib/runtime_tools/src/dbg.erl60
1 files changed, 30 insertions, 30 deletions
diff --git a/lib/runtime_tools/src/dbg.erl b/lib/runtime_tools/src/dbg.erl
index 186563ab74..c2de57d40b 100644
--- a/lib/runtime_tools/src/dbg.erl
+++ b/lib/runtime_tools/src/dbg.erl
@@ -778,50 +778,50 @@ tracer_init(Handler, HandlerData) ->
tracer_loop(Handler, HandlerData).
tracer_loop(Handler, Hdata) ->
- receive
- Msg ->
- %% Don't match in receive to avoid giving EXIT message higher
- %% priority than the trace messages.
- case Msg of
- {'EXIT',_Pid,_Reason} ->
- ok;
- Trace ->
- NewData = recv_all_traces(Trace, Handler, Hdata),
- tracer_loop(Handler, NewData)
- end
+ {State, Suspended, Traces} = recv_all_traces(),
+ NewHdata = handle_traces(Suspended, Traces, Handler, Hdata),
+ case State of
+ done ->
+ exit(normal);
+ loop ->
+ tracer_loop(Handler, NewHdata)
end.
-
-recv_all_traces(Trace, Handler, Hdata) ->
- Suspended = suspend(Trace, []),
- recv_all_traces(Suspended, Handler, Hdata, [Trace]).
-recv_all_traces(Suspended0, Handler, Hdata, Traces) ->
+recv_all_traces() ->
+ recv_all_traces([], [], infinity).
+
+recv_all_traces(Suspended0, Traces, Timeout) ->
receive
Trace when is_tuple(Trace), element(1, Trace) == trace ->
Suspended = suspend(Trace, Suspended0),
- recv_all_traces(Suspended, Handler, Hdata, [Trace|Traces]);
+ recv_all_traces(Suspended, [Trace|Traces], 0);
Trace when is_tuple(Trace), element(1, Trace) == trace_ts ->
Suspended = suspend(Trace, Suspended0),
- recv_all_traces(Suspended, Handler, Hdata, [Trace|Traces]);
+ recv_all_traces(Suspended, [Trace|Traces], 0);
Trace when is_tuple(Trace), element(1, Trace) == seq_trace ->
Suspended = suspend(Trace, Suspended0),
- recv_all_traces(Suspended, Handler, Hdata, [Trace|Traces]);
+ recv_all_traces(Suspended, [Trace|Traces], 0);
Trace when is_tuple(Trace), element(1, Trace) == drop ->
Suspended = suspend(Trace, Suspended0),
- recv_all_traces(Suspended, Handler, Hdata, [Trace|Traces]);
+ recv_all_traces(Suspended, [Trace|Traces], 0);
+ {'EXIT', _Pid, _Reason} ->
+ {done, Suspended0, Traces};
Other ->
%%% Is this really a good idea?
io:format(user,"** tracer received garbage: ~p~n", [Other]),
- recv_all_traces(Suspended0, Handler, Hdata, Traces)
- after 0 ->
- case catch invoke_handler(Traces, Handler, Hdata) of
- {'EXIT',Reason} ->
- resume(Suspended0),
- exit({trace_handler_crashed,Reason});
- NewHdata ->
- resume(Suspended0),
- NewHdata
- end
+ recv_all_traces(Suspended0, Traces, Timeout)
+ after Timeout ->
+ {loop, Suspended0, Traces}
+ end.
+
+handle_traces(Suspended, Traces, Handler, Hdata) ->
+ case catch invoke_handler(Traces, Handler, Hdata) of
+ {'EXIT',Reason} ->
+ resume(Suspended),
+ exit({trace_handler_crashed,Reason});
+ NewHdata ->
+ resume(Suspended),
+ NewHdata
end.
invoke_handler([Tr|Traces], Handler, Hdata0) ->