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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D50A2C433FF for ; Thu, 8 Aug 2019 01:08:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AE1B32184E for ; Thu, 8 Aug 2019 01:08:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730625AbfHHBIf (ORCPT ); Wed, 7 Aug 2019 21:08:35 -0400 Received: from smtprelay0081.hostedemail.com ([216.40.44.81]:59323 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1730467AbfHHBIf (ORCPT ); Wed, 7 Aug 2019 21:08:35 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay03.hostedemail.com (Postfix) with ESMTP id D47CE8368EFD; Thu, 8 Aug 2019 01:08:33 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: ear68_4a95da1cc8d30 X-Filterd-Recvd-Size: 4032 Received: from XPS-9350.home (cpe-23-242-196-136.socal.res.rr.com [23.242.196.136]) (Authenticated sender: joe@perches.com) by omf07.hostedemail.com (Postfix) with ESMTPA; Thu, 8 Aug 2019 01:08:32 +0000 (UTC) Message-ID: Subject: Re: [PATCH v2 2/2] linux/bits.h: Add compile time sanity check of GENMASK inputs From: Joe Perches To: Guenter Roeck , Masahiro Yamada , Linus Torvalds Cc: Rikard Falkeborn , Andrew Morton , Johannes Berg , Linux Kernel Mailing List Date: Wed, 07 Aug 2019 18:08:31 -0700 In-Reply-To: References: <20190731190309.19909-1-rikard.falkeborn@gmail.com> <20190801230358.4193-1-rikard.falkeborn@gmail.com> <20190801230358.4193-2-rikard.falkeborn@gmail.com> <20190807142728.GA16360@roeck-us.net> <099e07d4b4ecca9798404b95dc78c89bc3dd9f7f.camel@perches.com> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.30.5-0ubuntu0.18.10.1 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2019-08-07 at 17:58 -0700, Guenter Roeck wrote: > On 8/7/19 5:07 PM, Joe Perches wrote: > > On Wed, 2019-08-07 at 23:55 +0900, Masahiro Yamada wrote: > > > On Wed, Aug 7, 2019 at 11:27 PM Guenter Roeck wrote: > > [] > > > > Who is going to fix the fallout ? For example, arm64:defconfig no longer > > > > compiles with this patch applied. > > > > > > > > It seems to me that the benefit of catching misuses of GENMASK is much > > > > less than the fallout from no longer compiling kernels, since those > > > > kernels won't get any test coverage at all anymore. > > > > > > We cannot apply this until we fix all errors. > > > I do not understand why Andrew picked up this so soon. > > > > I think it makes complete sense to break -next (not mainline) > > and force people to fix defects. Especially these types of > > defects that are trivial to fix. > > > > I don't think this (from next-20190807): > > Build results: > total: 158 pass: 137 fail: 21 > Qemu test results: > total: 391 pass: 318 fail: 73 > > is very useful. The situation is bad enough for newly introduced problems. > It is all but impossible to get fixes for all problems discovered (or introduced) > by adding checks like this one. In some cases, no one will care. In others, > no one will pick up patches. Sometimes people won't know or realize that > they are expected to fix something. Making the situation worse, the failures > introduced by the new checks will hide other accumulating problems. > > arch/sh has failed to build in mainline since 7/27 and in -next since > next-20190711, due to the added "fallthrough" warning. I don't think > that is too useful either. Ok, that situation may be a sign that the > architecture isn't maintained as well as it should, but I don't think > that this warrants breaking it on purpose in the hope to trigger > some kind of reaction. > > I don't mind if new checks are introduced, and I agree that it is useful > and makes sense. But the checks should only be introduced after a reasonable > attempt was made to fix _all_ associated problems. That doesn't mean that > the entire work has to be done by the person introducing the check, but I > do see that person responsible for making sure (or a reasonable definition > of "make sure") that all problems are fixed before actually introducing > the check. Yes, I understand, this is a lot of work, but adding checks > and letting all hell break loose can not be the answer. No hell is unleashed. It's -next, an integration build, not mainline.