From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A5244C433B4 for ; Sun, 9 May 2021 22:55:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 84797613E8 for ; Sun, 9 May 2021 22:55:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230001AbhEIW4U (ORCPT ); Sun, 9 May 2021 18:56:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229840AbhEIW4T (ORCPT ); Sun, 9 May 2021 18:56:19 -0400 Received: from Chamillionaire.breakpoint.cc (Chamillionaire.breakpoint.cc [IPv6:2a0a:51c0:0:12e:520::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 73D8FC061573 for ; Sun, 9 May 2021 15:55:15 -0700 (PDT) Received: from fw by Chamillionaire.breakpoint.cc with local (Exim 4.92) (envelope-from ) id 1lfsKP-0003t2-Th; Mon, 10 May 2021 00:55:14 +0200 Date: Mon, 10 May 2021 00:55:13 +0200 From: Florian Westphal To: David Ahern Cc: Florian Westphal , netdev@vger.kernel.org Subject: Re: [PATCH iproute2] mptcp: avoid uninitialised errno usage Message-ID: <20210509225513.GF4038@breakpoint.cc> References: <20210503103631.30694-1-fw@strlen.de> <20210509222549.GE4038@breakpoint.cc> <3fc254ad-4766-a599-3500-ca16bd7d52c6@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3fc254ad-4766-a599-3500-ca16bd7d52c6@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org David Ahern wrote: > > if (rtnl_talk(grth, &req.n, &answer) < 0) { > > fprintf(stderr, "Error talking to the kernel\n"); > > + if (errno == 0) > > + errno = EOPNOTSUPP; > > you don't list the above string in the output in the commit log. Staring > at rtnl_talk and recvmsg and its failure paths, it seems unlikely that > path is causing the problem. Its not in my particular case, but if it would caller would still get random errno. The sketch I sent merely provides a relible errno whenever ret is less than 0. Right now it may or may not have been set.