From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754132AbaHEX7b (ORCPT ); Tue, 5 Aug 2014 19:59:31 -0400 Received: from mail-vc0-f171.google.com ([209.85.220.171]:56167 "EHLO mail-vc0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753885AbaHEX73 (ORCPT ); Tue, 5 Aug 2014 19:59:29 -0400 MIME-Version: 1.0 In-Reply-To: <20140805233058.GI13858@redhat.com> References: <20140730014827.565626091@linuxfoundation.org> <20140730014829.344302554@linuxfoundation.org> <20140730065312.GA1652@laptop.redhat.com> <20140805210728.GH13858@redhat.com> <20140805233058.GI13858@redhat.com> Date: Tue, 5 Aug 2014 16:59:28 -0700 X-Google-Sender-Auth: iOfvH-hhTh4dUvH0x96TUI7SBe4 Message-ID: Subject: Re: [PATCH 3.15 33/37] Fix gcc-4.9.0 miscompilation of load_balance() in scheduler From: Linus Torvalds To: "Frank Ch. Eigler" Cc: Josh Boyer , Jakub Jelinek , Greg Kroah-Hartman , Linux Kernel Mailing List , stable , =?UTF-8?Q?Michel_D=C3=A4nzer?= , Markus Trippelsdorf , Josh Stone Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 5, 2014 at 4:30 PM, Frank Ch. Eigler wrote: > > Would you consider a patch that does a gcc COMPARE_DEBUG-based test? Yes. But as mentioned, we don't have a really good way to do that. I guess we can do something similar to what "cc-option" does, but that will end up doing it for every single kernel build. I'd love to have something like this be done at kconfig time (along with all the *other* crazy conditional compiler options we do), but I guess that's a largely independent issue. And afaik, it will basically disallow every gcc version since 4.5 up until 4.9.2 gets released. And afaik, even current gcc actually fails the compare-debug test for at least some inputs, so ... Linus