From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf1-f197.google.com (mail-pf1-f197.google.com [209.85.210.197]) by kanga.kvack.org (Postfix) with ESMTP id C15FE8E001A for ; Wed, 23 Jan 2019 06:58:33 -0500 (EST) Received: by mail-pf1-f197.google.com with SMTP id b8so1538173pfe.10 for ; Wed, 23 Jan 2019 03:58:33 -0800 (PST) Received: from mail.kernel.org (mail.kernel.org. [198.145.29.99]) by mx.google.com with ESMTPS id d12si3943822pln.340.2019.01.23.03.58.32 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 23 Jan 2019 03:58:32 -0800 (PST) Date: Wed, 23 Jan 2019 12:58:29 +0100 From: Greg KH Subject: Re: [PATCH 1/3] treewide: Lift switch variables out of switches Message-ID: <20190123115829.GA31385@kroah.com> References: <20190123110349.35882-1-keescook@chromium.org> <20190123110349.35882-2-keescook@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190123110349.35882-2-keescook@chromium.org> Sender: owner-linux-mm@kvack.org List-ID: To: Kees Cook Cc: linux-kernel@vger.kernel.org, Ard Biesheuvel , Laura Abbott , Alexander Popov , xen-devel@lists.xenproject.org, dri-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, linux-usb@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, dev@openvswitch.org, linux-kbuild@vger.kernel.org, linux-security-module@vger.kernel.org, kernel-hardening@lists.openwall.com On Wed, Jan 23, 2019 at 03:03:47AM -0800, Kees Cook wrote: > Variables declared in a switch statement before any case statements > cannot be initialized, so move all instances out of the switches. > After this, future always-initialized stack variables will work > and not throw warnings like this: > > fs/fcntl.c: In function ‘send_sigio_to_task’: > fs/fcntl.c:738:13: warning: statement will never be executed [-Wswitch-unreachable] > siginfo_t si; > ^~ That's a pain, so this means we can't have any new variables in { } scope except for at the top of a function? That's going to be a hard thing to keep from happening over time, as this is valid C :( greg k-h