From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp57.i.mail.ru (smtp57.i.mail.ru [217.69.128.37]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id EC0CB46971A for ; Sun, 8 Dec 2019 22:28:37 +0300 (MSK) From: Vladislav Shpilevoy Date: Sun, 8 Dec 2019 20:28:32 +0100 Message-Id: In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Subject: [Tarantool-patches] [PATCH 1/2] fiber: unref fiber.storage via global Lua state List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: tarantool-patches@dev.tarantool.org, kostja.osipov@gmail.com, imun@tarantool.org Fiber.storage is a table, available from anywhere in the fiber. It is destroyed after fiber function is finished. That provides a reliable fiber-local storage, similar to thread-local in C/C++. But there is a problem that the storage may be created via one struct lua_State, and destroyed via another. Here is an example: function test_storage() fiber.self().storage.key = 100 end box.schema.func.create('test_storage') _ = fiber.create(function() box.func.test_storage:call() end) There are 3 struct lua_State: tarantool_L - global always alive Lua state; L1 - stack of the fiber, created by fiber.create(); L2 - stack created by that fiber to execute test_storage(). Fiber.storage is created on stack of L2 and referenced by global LUA_REGISTRYINDEX. Then it is unreferenced from L1 when the fiber is being destroyed. That is generally ok as soon as the storage object is always in LUA_REGISTRYINDEX, which is shared by all Lua states. But soon during destruction of the fiber.storage there will be only tarantool_L and the original L2. Original L2 may be already deleted by the time the storage is being destroyed. So this patch makes unref of the storage via reliable tarantool_L. Needed for #4662 --- src/lua/fiber.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/src/lua/fiber.c b/src/lua/fiber.c index 53ebec9aa..a7b75f9bf 100644 --- a/src/lua/fiber.c +++ b/src/lua/fiber.c @@ -445,7 +445,7 @@ lua_fiber_run_f(MAYBE_UNUSED va_list ap) /* Destroy local storage */ int storage_ref = f->storage.lua.ref; if (storage_ref > 0) - luaL_unref(L, LUA_REGISTRYINDEX, storage_ref); + luaL_unref(tarantool_L, LUA_REGISTRYINDEX, storage_ref); /* * If fiber is not joinable * We can unref child stack here, -- 2.21.0 (Apple Git-122.2)