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=-2.4 required=3.0 tests=GAPPY_SUBJECT, 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 CC9B0C0650E for ; Sat, 6 Jul 2019 19:29:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ADF9A20838 for ; Sat, 6 Jul 2019 19:29:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727071AbfGFT27 (ORCPT ); Sat, 6 Jul 2019 15:28:59 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:59086 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726743AbfGFT26 (ORCPT ); Sat, 6 Jul 2019 15:28:58 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux)) id 1hjqMf-0002wo-4P; Sat, 06 Jul 2019 19:28:53 +0000 Date: Sat, 6 Jul 2019 20:28:53 +0100 From: Al Viro To: Salvatore Mesoraca Cc: linux-kernel@vger.kernel.org, kernel-hardening@lists.openwall.com, linux-mm@kvack.org, linux-security-module@vger.kernel.org, Brad Spengler , Casey Schaufler , Christoph Hellwig , James Morris , Jann Horn , Kees Cook , PaX Team , "Serge E. Hallyn" , Thomas Gleixner Subject: Re: [PATCH v5 06/12] S.A.R.A.: WX protection Message-ID: <20190706192852.GO17978@ZenIV.linux.org.uk> References: <1562410493-8661-1-git-send-email-s.mesoraca16@gmail.com> <1562410493-8661-7-git-send-email-s.mesoraca16@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1562410493-8661-7-git-send-email-s.mesoraca16@gmail.com> User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jul 06, 2019 at 12:54:47PM +0200, Salvatore Mesoraca wrote: > +#define sara_warn_or_return(err, msg) do { \ > + if ((sara_wxp_flags & SARA_WXP_VERBOSE)) \ > + pr_wxp(msg); \ > + if (!(sara_wxp_flags & SARA_WXP_COMPLAIN)) \ > + return -err; \ > +} while (0) > + > +#define sara_warn_or_goto(label, msg) do { \ > + if ((sara_wxp_flags & SARA_WXP_VERBOSE)) \ > + pr_wxp(msg); \ > + if (!(sara_wxp_flags & SARA_WXP_COMPLAIN)) \ > + goto label; \ > +} while (0) No. This kind of "style" has no place in the kernel. Don't hide control flow. It's nasty enough to reviewers, but it's pure hell on anyone who strays into your code while chasing a bug or doing general code audit. In effect, you are creating your oh-so-private C dialect and assuming that everyone who ever looks at your code will start with learning that *AND* incorporating it into their mental C parser. I'm sorry, but you are not that important. If it looks like a function call, a casual reader will assume that this is exactly what it is. And when one is scanning through a function (e.g. to tell if handling of some kind of refcounts is correct, with twentieth grep through the tree having brought something in your code into the view), the last thing one wants is to switch between the area-specific C dialects. Simply because looking at yours is sandwiched between digging through some crap in drivers/target/ and that weird thing in kernel/tracing/, hopefully staying limited to 20 seconds of glancing through several functions in your code. Don't Do That. Really.