From 754e2022059864f2c4025ab67da759bde922a066 Mon Sep 17 00:00:00 2001
From: Lukas Larsson <lukas@erlang.org>
Date: Tue, 4 Dec 2018 10:10:37 +0100
Subject: erts: Fix copy of literal msg during gc
A copy has to be made of the message as there is
a trace token. There was a bug where the actual
message was incorrectly modified even if it was a
literal.
---
erts/emulator/beam/erl_gc.c | 2 +-
lib/kernel/test/seq_trace_SUITE.erl | 39 ++++++++++++++++++++++++++++++++-----
2 files changed, 35 insertions(+), 6 deletions(-)
diff --git a/erts/emulator/beam/erl_gc.c b/erts/emulator/beam/erl_gc.c
index b4df418cd5..d5dfb096b1 100644
--- a/erts/emulator/beam/erl_gc.c
+++ b/erts/emulator/beam/erl_gc.c
@@ -2477,7 +2477,7 @@ erts_copy_one_frag(Eterm** hpp, ErlOffHeap* off_heap,
*hpp = hp;
for (i = 0; i < nrefs; i++) {
- if (is_not_immed(refs[i]))
+ if (is_not_immed(refs[i]) && !erts_is_literal(refs[i],boxed_val(refs[i])))
refs[i] = offset_ptr(refs[i], offs);
}
bp->off_heap.first = NULL;
diff --git a/lib/kernel/test/seq_trace_SUITE.erl b/lib/kernel/test/seq_trace_SUITE.erl
index cf4bf11328..ee8f4e94f8 100644
--- a/lib/kernel/test/seq_trace_SUITE.erl
+++ b/lib/kernel/test/seq_trace_SUITE.erl
@@ -25,7 +25,8 @@
-export([token_set_get/1, tracer_set_get/1, print/1,
send/1, distributed_send/1, recv/1, distributed_recv/1,
trace_exit/1, distributed_exit/1, call/1, port/1,
- match_set_seq_token/1, gc_seq_token/1, label_capability_mismatch/1]).
+ match_set_seq_token/1, gc_seq_token/1, label_capability_mismatch/1,
+ send_literal/1]).
%% internal exports
-export([simple_tracer/2, one_time_receiver/0, one_time_receiver/1,
@@ -44,7 +45,7 @@ suite() ->
{timetrap,{minutes,1}}].
all() ->
- [token_set_get, tracer_set_get, print, send,
+ [token_set_get, tracer_set_get, print, send, send_literal,
distributed_send, recv, distributed_recv, trace_exit,
distributed_exit, call, port, match_set_seq_token,
gc_seq_token, label_capability_mismatch].
@@ -158,23 +159,51 @@ do_print(TsType) ->
{0,{print,_,_,[],print3}, Ts1}] = stop_tracer(2),
check_ts(TsType, Ts0),
check_ts(TsType, Ts1).
-
+
send(Config) when is_list(Config) ->
lists:foreach(fun do_send/1, ?TIMESTAMP_MODES).
do_send(TsType) ->
+ do_send(TsType, send).
+
+do_send(TsType, Msg) ->
seq_trace:reset_trace(),
start_tracer(),
Receiver = spawn(?MODULE,one_time_receiver,[]),
Label = make_ref(),
seq_trace:set_token(label,Label),
set_token_flags([send, TsType]),
- Receiver ! send,
+ Receiver ! Msg,
Self = self(),
seq_trace:reset_trace(),
- [{Label,{send,_,Self,Receiver,send}, Ts}] = stop_tracer(1),
+ [{Label,{send,_,Self,Receiver,Msg}, Ts}] = stop_tracer(1),
check_ts(TsType, Ts).
+%% This testcase tests that we do not segfault when we have a
+%% literal as the message and the message is copied onto the
+%% heap during a GC.
+send_literal(Config) when is_list(Config) ->
+ lists:foreach(fun do_send_literal/1,
+ [atom, make_ref(), ets:new(hej,[]), 1 bsl 64,
+ "gurka", {tuple,test,with,#{}}, #{}]).
+
+do_send_literal(Msg) ->
+ N = 10000,
+ seq_trace:reset_trace(),
+ start_tracer(),
+ Label = make_ref(),
+ seq_trace:set_token(label,Label),
+ set_token_flags([send, 'receive', no_timestamp]),
+ Receiver = spawn_link(fun() -> receive ok -> ok end end),
+ [Receiver ! Msg || _ <- lists:seq(1, N)],
+ erlang:garbage_collect(Receiver),
+ [Receiver ! Msg || _ <- lists:seq(1, N)],
+ erlang:garbage_collect(Receiver),
+ Self = self(),
+ seq_trace:reset_trace(),
+ [{Label,{send,_,Self,Receiver,Msg}, Ts} | _] = stop_tracer(N),
+ check_ts(no_timestamp, Ts).
+
distributed_send(Config) when is_list(Config) ->
lists:foreach(fun do_distributed_send/1, ?TIMESTAMP_MODES).
--
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