From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Tue, 7 Aug 2018 14:09:01 +0300 From: Vladimir Davydov Subject: Re: [PATCH] box: serialize calls to box.cfg Message-ID: <20180807110901.z3thcmcwkt3qkyrm@esperanza> References: <619fdb85de8edff29334abcf75ffec7aa8647723.1533634796.git.vdavydov.dev@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <619fdb85de8edff29334abcf75ffec7aa8647723.1533634796.git.vdavydov.dev@gmail.com> To: georgy@tarantool.org Cc: tarantool-patches@freelists.org List-ID: On Tue, Aug 07, 2018 at 12:43:26PM +0300, Vladimir Davydov wrote: > It is dangerous to call box.cfg() concurrently from different fibers. > For example, replication configuration uses static variables and yields > so calling it concurrently can result in a crash. To make sure it never > happens, let's protect box.cfg() with a lock. > > Closes #3606 > --- > https://github.com/tarantool/tarantool/issues/3606 > https://github.com/tarantool/tarantool/tree/dv/gh-3606-concurrent-replication-cfg-fix > > src/box/lua/load_cfg.lua | 21 ++++++++++++++++++--- > test/replication/misc.result | 24 ++++++++++++++++++++++++ > test/replication/misc.test.lua | 10 ++++++++++ > 3 files changed, 52 insertions(+), 3 deletions(-) > > diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua > index 0b668cdc..4de79220 100644 > --- a/src/box/lua/load_cfg.lua > +++ b/src/box/lua/load_cfg.lua > @@ -5,6 +5,21 @@ local json = require('json') > local private = require('box.internal') > local urilib = require('uri') > local math = require('math') > +local fiber = require('fiber') > + > +-- Function decorator that is used to prevent box.cfg() from > +-- being called concurrently by different fibers. > +local lock = fiber.channel(1) > +local function locked(f) > + return function(...) > + lock:put(true) > + local status = pcall(f, ...) > + lock:get() > + if not status then > + box.error() > + end > + end > +end Georgy noted that we'd better use error() to re-throw the error returned by box.cfg(). Updated on the branch, the incremental diff is below: diff --git a/src/box/lua/load_cfg.lua b/src/box/lua/load_cfg.lua index 4de79220..c68a3583 100644 --- a/src/box/lua/load_cfg.lua +++ b/src/box/lua/load_cfg.lua @@ -13,10 +13,10 @@ local lock = fiber.channel(1) local function locked(f) return function(...) lock:put(true) - local status = pcall(f, ...) + local status, err = pcall(f, ...) lock:get() if not status then - box.error() + error(err) end end end