From 4082c3d1ad3d0e8bb85706c5f3b2bde97bb43fcb Mon Sep 17 00:00:00 2001 From: Sverker Eriksson Date: Wed, 5 Feb 2014 19:41:28 +0100 Subject: erts: Fix NIF bug when load/upgrade fails after enif_open_resource_type ..has been successfully called. Opened resource types (created or taken-over) were left "hanging" leading both to memory leakage and other more strange and serious behavior. Now a proper rollback is done. --- erts/emulator/beam/erl_nif.c | 113 ++++++++++++++++++++++++++++++++++--------- 1 file changed, 91 insertions(+), 22 deletions(-) (limited to 'erts/emulator/beam') diff --git a/erts/emulator/beam/erl_nif.c b/erts/emulator/beam/erl_nif.c index dc285b3cf7..b2fd3dcd24 100644 --- a/erts/emulator/beam/erl_nif.c +++ b/erts/emulator/beam/erl_nif.c @@ -1,7 +1,7 @@ /* * %CopyrightBegin% * - * Copyright Ericsson AB 2009-2013. All Rights Reserved. + * Copyright Ericsson AB 2009-2014. All Rights Reserved. * * The contents of this file are subject to the Erlang Public License, * Version 1.1, (the "License"); you may not use this file except in @@ -1235,6 +1235,19 @@ static void steal_resource_type(ErlNifResourceType* type) } } +/* The opened_rt_list is used by enif_open_resource_type() + * in order to rollback "creates" and "take-overs" in case the load fails. + */ +struct opened_resource_type +{ + struct opened_resource_type* next; + + ErlNifResourceFlags op; + ErlNifResourceType* type; + ErlNifResourceDtor* new_dtor; +}; +static struct opened_resource_type* opened_rt_list = NULL; + ErlNifResourceType* enif_open_resource_type(ErlNifEnv* env, const char* module_str, @@ -1256,22 +1269,21 @@ enif_open_resource_type(ErlNifEnv* env, if (type == NULL) { if (flags & ERL_NIF_RT_CREATE) { type = erts_alloc(ERTS_ALC_T_NIF, - sizeof(struct enif_resource_type_t)); - type->dtor = dtor; + sizeof(struct enif_resource_type_t)); type->module = module_am; type->name = name_am; erts_refc_init(&type->refc, 1); - type->owner = env->mod_nif; - type->prev = &resource_type_list; - type->next = resource_type_list.next; - type->next->prev = type; - type->prev->next = type; op = ERL_NIF_RT_CREATE; + #ifdef DEBUG + type->dtor = (void*)1; + type->owner = (void*)2; + type->prev = (void*)3; + type->next = (void*)4; + #endif } } else { - if (flags & ERL_NIF_RT_TAKEOVER) { - steal_resource_type(type); + if (flags & ERL_NIF_RT_TAKEOVER) { op = ERL_NIF_RT_TAKEOVER; } else { @@ -1279,12 +1291,13 @@ enif_open_resource_type(ErlNifEnv* env, } } if (type != NULL) { - type->owner = env->mod_nif; - type->dtor = dtor; - if (type->dtor != NULL) { - erts_refc_inc(&type->owner->rt_dtor_cnt, 1); - } - erts_refc_inc(&type->owner->rt_cnt, 1); + struct opened_resource_type* ort = erts_alloc(ERTS_ALC_T_TMP, + sizeof(struct opened_resource_type)); + ort->op = op; + ort->type = type; + ort->new_dtor = dtor; + ort->next = opened_rt_list; + opened_rt_list = ort; } if (tried != NULL) { *tried = op; @@ -1292,6 +1305,51 @@ enif_open_resource_type(ErlNifEnv* env, return type; } +static void commit_opened_resource_types(struct erl_module_nif* lib) +{ + while (opened_rt_list) { + struct opened_resource_type* ort = opened_rt_list; + + ErlNifResourceType* type = ort->type; + + if (ort->op == ERL_NIF_RT_CREATE) { + type->prev = &resource_type_list; + type->next = resource_type_list.next; + type->next->prev = type; + type->prev->next = type; + } + else { /* ERL_NIF_RT_TAKEOVER */ + steal_resource_type(type); + } + + type->owner = lib; + type->dtor = ort->new_dtor; + + if (type->dtor != NULL) { + erts_refc_inc(&lib->rt_dtor_cnt, 1); + } + erts_refc_inc(&lib->rt_cnt, 1); + + opened_rt_list = ort->next; + erts_free(ERTS_ALC_T_TMP, ort); + } +} + +static void rollback_opened_resource_types(void) +{ + while (opened_rt_list) { + struct opened_resource_type* ort = opened_rt_list; + + if (ort->op == ERL_NIF_RT_CREATE) { + erts_free(ERTS_ALC_T_NIF, ort->type); + } + + opened_rt_list = ort->next; + erts_free(ERTS_ALC_T_TMP, ort); + } +} + + static void nif_resource_dtor(Binary* bin) { ErlNifResource* resource = (ErlNifResource*) ERTS_MAGIC_BIN_DATA(bin); @@ -1317,6 +1375,8 @@ void* enif_alloc_resource(ErlNifResourceType* type, size_t size) { Binary* bin = erts_create_magic_binary(SIZEOF_ErlNifResource(size), &nif_resource_dtor); ErlNifResource* resource = ERTS_MAGIC_BIN_DATA(bin); + + ASSERT(type->owner && type->next && type->prev); /* not allowed in load/upgrade */ resource->type = type; erts_refc_inc(&bin->refc, 1); #ifdef DEBUG @@ -1696,9 +1756,15 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2) lib->entry = entry; erts_refc_init(&lib->rt_cnt, 0); erts_refc_init(&lib->rt_dtor_cnt, 0); + ASSERT(opened_rt_list == NULL); lib->mod = mod; env.mod_nif = lib; - if (mod->curr.nif != NULL) { /* Reload */ + if (mod->curr.nif != NULL) { /*************** Reload ******************/ + /* + * Repeated load_nif calls from same Erlang module instance ("reload") + * is deprecated and was only ment as a development feature not to + * be used in production systems. (See warning below) + */ int k; lib->priv_data = mod->curr.nif->priv_data; @@ -1730,6 +1796,7 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2) ret = load_nif_error(BIF_P, reload, "Library reload-call unsuccessful."); } else { + commit_opened_resource_types(lib); mod->curr.nif->entry = NULL; /* to prevent 'unload' callback */ erts_unload_nif(mod->curr.nif); reload_warning = 1; @@ -1737,7 +1804,7 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2) } else { lib->priv_data = NULL; - if (mod->old.nif != NULL) { /* Upgrade */ + if (mod->old.nif != NULL) { /**************** Upgrade ***************/ void* prev_old_data = mod->old.nif->priv_data; if (entry->upgrade == NULL) { ret = load_nif_error(BIF_P, upgrade, "Upgrade not supported by this NIF library."); @@ -1750,17 +1817,18 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2) mod->old.nif->priv_data = prev_old_data; ret = load_nif_error(BIF_P, upgrade, "Library upgrade-call unsuccessful."); } - /*else if (mod->old_nif->priv_data != prev_old_data) { - refresh_cached_nif_data(mod->old_code, mod->old_nif); - }*/ + else + commit_opened_resource_types(lib); } - else if (entry->load != NULL) { /* Initial load */ + else if (entry->load != NULL) { /********* Initial load ***********/ erts_pre_nif(&env, BIF_P, lib); veto = entry->load(&env, &lib->priv_data, BIF_ARG_2); erts_post_nif(&env); if (veto) { ret = load_nif_error(BIF_P, "load", "Library load-call unsuccessful."); } + else + commit_opened_resource_types(lib); } } if (ret == am_ok) { @@ -1789,6 +1857,7 @@ BIF_RETTYPE load_nif_2(BIF_ALIST_2) } else { error: + rollback_opened_resource_types(); ASSERT(ret != am_ok); if (lib != NULL) { erts_free(ERTS_ALC_T_NIF, lib); -- cgit v1.2.3