From c70ca686fe269db6079a2ca1c7e09cdfc0cfa903 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Bj=C3=B6rn=20Gustavsson?= Date: Mon, 5 Sep 2016 16:16:23 +0200 Subject: Don't leak old code when loading a modules with an on_load function Normally, calling code:delete/1 before re-loading the code for a module is unnecessary but causes no problem. But there will be be problems if the new code has an on_load function. Code with an on_load function will always be loaded as old code to allowed it to be easily purged if the on_load function would fail. If the on_load function succeeds, the old and current code will be swapped. So in the scenario where code:delete/1 has been called explicitly, there is old code but no current code. Loading code with an on_load function will cause the reference to the old code to be overwritten. That will at best cause a memory leak, and at worst an emulator crash (especially if NIFs are involved). To avoid that situation, we will put the code with the on_load function in a special, third slot in Module. ERL-240 --- lib/kernel/src/code_server.erl | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'lib/kernel/src') diff --git a/lib/kernel/src/code_server.erl b/lib/kernel/src/code_server.erl index 48541ec500..38c1169308 100644 --- a/lib/kernel/src/code_server.erl +++ b/lib/kernel/src/code_server.erl @@ -1382,11 +1382,10 @@ finish_on_load(PidRef, OnLoadRes, #state{on_load=OnLoad0}=St0) -> finish_on_load_1(Mod, OnLoadRes, Waiting, St) -> Keep = OnLoadRes =:= ok, - erlang:finish_after_on_load(Mod, Keep), + erts_code_purger:finish_after_on_load(Mod, Keep), Res = case Keep of false -> _ = finish_on_load_report(Mod, OnLoadRes), - _ = erts_code_purger:purge(Mod), {error,on_load_failure}; true -> {module,Mod} -- cgit v1.2.3