From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp45.i.mail.ru (smtp45.i.mail.ru [94.100.177.105]) (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 AEE76469719 for ; Thu, 24 Sep 2020 12:32:45 +0300 (MSK) Date: Thu, 24 Sep 2020 12:32:54 +0300 From: Alexander Turenko Message-ID: <20200924093254.dhm4hzlerfwftfkn@tkn_work_nb> References: <20200921174837.30681-1-skaplun@tarantool.org> <20200923231619.samgq6wp44dhjjdp@tkn_work_nb> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20200923231619.samgq6wp44dhjjdp@tkn_work_nb> Subject: Re: [Tarantool-patches] [PATCH] cppcheck: src/lua/fiber.c null pointer dereference List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Sergey Kaplun Cc: tarantool-patches@dev.tarantool.org On Thu, Sep 24, 2020 at 02:16:20AM +0300, Alexander Turenko wrote: > On Mon, Sep 21, 2020 at 08:48:37PM +0300, Sergey Kaplun wrote: > > Found and fixed possible null pointer dereference with cppcheck: > > > > [src/lua/fiber.c:245] -> [src/lua/fiber.c:217]: (warning) Either the condition 'if(func)' is redundant or there is possible null pointer dereference: func. > > Nit: I think there is nothing bad in carrying one-line non-prose text > like an error message from some tool. It looks more pretty this way, > IMHO. > > The first question that comes into my mind: whether the NULL dereference > may occur before the patch or it is the false positive. It is nice, when > it is investigated and described right in the commit message. > > In fact it influences how we take the patch: whether it is bugfix or > refactoring. Bugfixes are usually included into future release notes (it > is user visible change), but refactoring usually is not. Aside of this point (and the nit below), the patch is okay. LGTM except those points. > > > --- > > > > Branch: https://github.com/tarantool/tarantool/tree/skaplun/cppcheck-lua-fiber-possible-null-pointer-dereference > > > > 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 45bc03787..bb6212b24 100644 > > --- a/src/lua/fiber.c > > +++ b/src/lua/fiber.c > > @@ -214,7 +214,7 @@ fiber_backtrace_cb(int frameno, void *frameret, const char *func, size_t offset, > > { > > struct lua_fiber_tb_ctx *tb_ctx = (struct lua_fiber_tb_ctx *)cb_ctx; > > struct lua_State *L = tb_ctx->L; > > - if (strstr(func, "lj_BC_FUNCC") == func) { > > + if (func && strstr(func, "lj_BC_FUNCC") == func) { > > Nit: We usually explicitly check against NULL (or 0 for an integer type). This nit, I meant. > I was wonder whether 'func' actually can be NULL and found that there is > no error handling around unw_get_proc_name(). We ignore its return value > and just return content of our thread local buffer (not NULL). Moved to https://github.com/tarantool/tarantool/issues/5326