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authorJohn Högberg <[email protected]>2018-06-14 08:26:07 +0200
committerJohn Högberg <[email protected]>2018-06-14 08:26:07 +0200
commit8ca58cf82e430775ab1c2adfab31f77f649c3f96 (patch)
treedb259111fd981940331fa9c3bfb0a85bc746a8eb /erts/emulator/test
parent4013f4840d8d540c63fa7901c2d8d1653ae45821 (diff)
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Don't enqueue system tasks if target process is in fail_state
The fail state wasn't re-checked in the state change loop; only the FREE state was checked. In addition to that, we would leave the task in the queue when bailing out which could lead to a double-free. This commit backports active_sys_enqueue from master to make it easier to merge onwards.
Diffstat (limited to 'erts/emulator/test')
-rw-r--r--erts/emulator/test/process_SUITE.erl54
1 files changed, 53 insertions, 1 deletions
diff --git a/erts/emulator/test/process_SUITE.erl b/erts/emulator/test/process_SUITE.erl
index a8bcfac84d..899a5c26bd 100644
--- a/erts/emulator/test/process_SUITE.erl
+++ b/erts/emulator/test/process_SUITE.erl
@@ -58,6 +58,7 @@
no_priority_inversion2/1,
system_task_blast/1,
system_task_on_suspended/1,
+ system_task_failed_enqueue/1,
gc_request_when_gc_disabled/1,
gc_request_blast_when_gc_disabled/1]).
-export([prio_server/2, prio_client/2, init/1, handle_event/2]).
@@ -104,7 +105,7 @@ groups() ->
otp_7738_resume]},
{system_task, [],
[no_priority_inversion, no_priority_inversion2,
- system_task_blast, system_task_on_suspended,
+ system_task_blast, system_task_on_suspended, system_task_failed_enqueue,
gc_request_when_gc_disabled, gc_request_blast_when_gc_disabled]}].
init_per_suite(Config) ->
@@ -2531,6 +2532,57 @@ system_task_on_suspended(Config) when is_list(Config) ->
ok
end.
+%% When a system task couldn't be enqueued due to the process being in an
+%% incompatible state, it would linger in the system task list and get executed
+%% anyway the next time the process was scheduled. This would result in a
+%% double-free at best.
+%%
+%% This test continuously purges modules while other processes run dirty code,
+%% which will provoke this error as ERTS_PSTT_CPC can't be enqueued while a
+%% process is running dirty code.
+system_task_failed_enqueue(Config) when is_list(Config) ->
+ case erlang:system_info(dirty_cpu_schedulers) of
+ N when N > 0 ->
+ system_task_failed_enqueue_1(Config);
+ _ ->
+ {skipped, "No dirty scheduler support"}
+ end.
+
+system_task_failed_enqueue_1(Config) ->
+ Priv = proplists:get_value(priv_dir, Config),
+
+ Purgers = [spawn_link(fun() -> purge_loop(Priv, Id) end)
+ || Id <- lists:seq(1, erlang:system_info(schedulers))],
+ Hogs = [spawn_link(fun() -> dirty_loop() end)
+ || _ <- lists:seq(1, erlang:system_info(dirty_cpu_schedulers))],
+
+ ct:sleep(5000),
+
+ [begin
+ unlink(Pid),
+ exit(Pid, kill)
+ end || Pid <- (Purgers ++ Hogs)],
+
+ ok.
+
+purge_loop(PrivDir, Id) ->
+ Mod = "failed_enq_" ++ integer_to_list(Id),
+ Path = PrivDir ++ "/" ++ Mod,
+ file:write_file(Path ++ ".erl",
+ "-module('" ++ Mod ++ "').\n" ++
+ "-export([t/0]).\n" ++
+ "t() -> ok."),
+ purge_loop_1(Path).
+purge_loop_1(Path) ->
+ {ok, Mod} = compile:file(Path, []),
+ erlang:delete_module(Mod),
+ erts_code_purger:purge(Mod),
+ purge_loop_1(Path).
+
+dirty_loop() ->
+ ok = erts_debug:dirty_cpu(reschedule, 10000),
+ dirty_loop().
+
gc_request_when_gc_disabled(Config) when is_list(Config) ->
AIS = erts_debug:set_internal_state(available_internal_state, true),
gc_request_when_gc_disabled_do(ref),