From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org> To: tarantool-patches@dev.tarantool.org, kostja.osipov@gmail.com, imun@tarantool.org Subject: [Tarantool-patches] [PATCH 1/2] fiber: unref fiber.storage via global Lua state Date: Sun, 8 Dec 2019 20:28:32 +0100 [thread overview] Message-ID: <b58dce9ba1ef11c4eb0272450b66b1fce0558f67.1575833120.git.v.shpilevoy@tarantool.org> (raw) In-Reply-To: <cover.1575833120.git.v.shpilevoy@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)
next prev parent reply other threads:[~2019-12-08 19:28 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-12-08 19:28 [Tarantool-patches] [PATCH 0/2] Fiber storage leak Vladislav Shpilevoy 2019-12-08 19:28 ` Vladislav Shpilevoy [this message] 2019-12-11 23:57 ` [Tarantool-patches] [PATCH 1/2] fiber: unref fiber.storage via global Lua state Igor Munkin 2019-12-12 8:50 ` Konstantin Osipov 2019-12-12 23:38 ` Vladislav Shpilevoy 2019-12-13 10:44 ` Igor Munkin 2019-12-08 19:28 ` [Tarantool-patches] [PATCH 2/2] fiber: destroy fiber.storage created by iproto Vladislav Shpilevoy 2019-12-09 7:21 ` Konstantin Osipov 2019-12-09 23:31 ` Vladislav Shpilevoy 2019-12-10 8:21 ` Konstantin Osipov 2019-12-10 8:32 ` Konstantin Osipov 2019-12-10 22:59 ` Vladislav Shpilevoy 2019-12-11 7:08 ` Konstantin Osipov 2019-12-11 21:23 ` Vladislav Shpilevoy 2019-12-12 0:00 ` Igor Munkin 2019-12-12 23:37 ` Vladislav Shpilevoy 2019-12-13 13:35 ` Igor Munkin 2019-12-12 8:46 ` Konstantin Osipov 2019-12-13 0:02 ` Vladislav Shpilevoy 2019-12-13 7:58 ` Konstantin Osipov 2019-12-13 23:11 ` Vladislav Shpilevoy 2019-12-14 12:26 ` Konstantin Osipov 2019-12-14 12:30 ` Konstantin Osipov 2019-12-14 12:33 ` Konstantin Osipov 2019-12-14 16:49 ` Vladislav Shpilevoy 2019-12-14 20:59 ` Vladislav Shpilevoy
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