proc_lib: Don't call erlang:get_stacktrace/0 twice

proc_lib calls erlang:get_stacktrace/0 twice, which is unnecessary,
and potentially unsafe since there are calls to many functions
in between. Any of the calls could potentially cause and catch
an exception, invalidating the stacktrace.

Only call erlang:get_stacktrace/0 once, and pass the result to
the second place where it is needed.

1 files changed, 14 insertions, 13 deletions

diff --git a/lib/stdlib/src/proc_lib.erl b/lib/stdlib/src/proc_lib.erl
index 363705b0f4..2219467a8d 100644
--- a/lib/stdlib/src/proc_lib.erl
+++ b/lib/stdlib/src/proc_lib.erl
@@ -264,12 +264,12 @@ exit_p(Class, Reason, Stacktrace) ->
     case get('$initial_call') of
 	{M,F,A} when is_atom(M), is_atom(F), is_integer(A) ->
 	    MFA = {M,F,make_dummy_args(A, [])},
-	    crash_report(Class, Reason, MFA),
+	    crash_report(Class, Reason, MFA, Stacktrace),
 	    erlang:raise(exit, exit_reason(Class, Reason, Stacktrace), Stacktrace);
 	_ ->
 	    %% The process dictionary has been cleared or
 	    %% possibly modified.
-	    crash_report(Class, Reason, []),
+	    crash_report(Class, Reason, [], Stacktrace),
 	    erlang:raise(exit, exit_reason(Class, Reason, Stacktrace), Stacktrace)
     end.
 
@@ -499,24 +499,25 @@ trans_init(M, F, A) when is_atom(M), is_atom(F) ->
 %% Generate a crash report.
 %% -----------------------------------------------------
 
-crash_report(exit, normal, _)       -> ok;
-crash_report(exit, shutdown, _)     -> ok;
-crash_report(exit, {shutdown,_}, _) -> ok;
-crash_report(Class, Reason, StartF) ->
-    OwnReport = my_info(Class, Reason, StartF),
+crash_report(exit, normal, _, _)       -> ok;
+crash_report(exit, shutdown, _, _)     -> ok;
+crash_report(exit, {shutdown,_}, _, _) -> ok;
+crash_report(Class, Reason, StartF, Stacktrace) ->
+    OwnReport = my_info(Class, Reason, StartF, Stacktrace),
     LinkReport = linked_info(self()),
     Rep = [OwnReport,LinkReport],
     error_logger:error_report(crash_report, Rep).
 
-my_info(Class, Reason, []) ->
-    my_info_1(Class, Reason);
-my_info(Class, Reason, StartF) ->
-    [{initial_call, StartF}|my_info_1(Class, Reason)].
+my_info(Class, Reason, [], Stacktrace) ->
+    my_info_1(Class, Reason, Stacktrace);
+my_info(Class, Reason, StartF, Stacktrace) ->
+    [{initial_call, StartF}|
+     my_info_1(Class, Reason, Stacktrace)].
 
-my_info_1(Class, Reason) ->
+my_info_1(Class, Reason, Stacktrace) ->
     [{pid, self()},
      get_process_info(self(), registered_name),         
-     {error_info, {Class,Reason,erlang:get_stacktrace()}}, 
+     {error_info, {Class,Reason,Stacktrace}},
      get_ancestors(self()),        
      get_process_info(self(), messages),
      get_process_info(self(), links),