From: Vladislav Shpilevoy <v.shpilevoy@tarantool.org> To: tarantool-patches@dev.tarantool.org, kostja.osipov@gmail.com Subject: [Tarantool-patches] [PATCH v2 1/3] fiber: unref fiber.storage via global Lua state Date: Thu, 16 Jan 2020 22:54:21 +0100 [thread overview] Message-ID: <cc66ca5fc1c0a20c5b44ff150c455b4499e9e9cc.1579211601.git.v.shpilevoy@tarantool.org> (raw) In-Reply-To: <cover.1579211601.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 state; L1 - Lua coroutine of the fiber, created by fiber.create(); L2 - Lua coroutine 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, -- 2.21.1 (Apple Git-122.3)
next prev parent reply other threads:[~2020-01-16 21:54 UTC|newest] Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-01-16 21:54 [Tarantool-patches] [PATCH v2 0/3] Fiber storage leak Vladislav Shpilevoy 2020-01-16 21:54 ` Vladislav Shpilevoy [this message] 2020-01-17 7:30 ` [Tarantool-patches] [PATCH v2 1/3] fiber: unref fiber.storage via global Lua state Konstantin Osipov 2020-01-16 21:54 ` [Tarantool-patches] [PATCH v2 2/3] fiber: destroy fiber.storage created by iproto Vladislav Shpilevoy 2020-01-16 22:00 ` Cyrill Gorcunov 2020-01-17 7:47 ` Konstantin Osipov 2020-01-17 8:06 ` Cyrill Gorcunov 2020-01-17 7:45 ` Konstantin Osipov 2020-01-19 17:32 ` Vladislav Shpilevoy 2020-01-20 7:22 ` Konstantin Osipov 2020-01-20 19:15 ` Georgy Kirichenko 2020-01-21 22:21 ` Vladislav Shpilevoy 2020-01-21 22:32 ` Konstantin Osipov 2020-01-16 21:54 ` [Tarantool-patches] [PATCH v2 3/3] box: remove dead code from box_process_call/eval() Vladislav Shpilevoy 2020-01-17 7:46 ` Konstantin Osipov 2020-01-17 7:47 ` Konstantin Osipov 2020-01-17 17:41 ` Georgy Kirichenko 2020-01-19 17:32 ` Vladislav Shpilevoy 2020-01-20 19:21 ` Georgy Kirichenko 2020-01-18 19:27 ` [Tarantool-patches] [PATCH v2 0/3] Fiber storage leak Igor Munkin 2020-02-15 1:02 ` Vladislav Shpilevoy
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