Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1428607AbdDYJWg (ORCPT ); Tue, 25 Apr 2017 05:22:36 -0400 Received: from foss.arm.com ([217.140.101.70]:38258 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1177307AbdDYJW1 (ORCPT ); Tue, 25 Apr 2017 05:22:27 -0400 Subject: Re: [RFC] minimum gcc version for kernel: raise to gcc-4.3 or 4.6? To: Kees Cook References: <20161216105634.235457-1-arnd@arndb.de> <3302470.IDcDrWa0u6@wuerfel> Cc: Arnd Bergmann , linux-arch , linux-kbuild , kernel-build-reports@lists.linaro.org, LKML , Russell King , Andrew Morton , kvmarm@lists.cs.columbia.edu, "linux-arm-kernel@lists.infradead.org" From: Suzuki K Poulose Message-ID: Date: Tue, 25 Apr 2017 10:22:23 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1996 Lines: 53 On 16/04/17 20:52, Kees Cook wrote: > Was there a conclusion to this discussion? I didn't see anything > definitive in the thread... > > Notes below... > > On Fri, Dec 16, 2016 at 3:14 AM, Arnd Bergmann wrote: >> [Fixed linux-arm-kernel mailing list address, sorry for the duplicate, >> I'm not reposting all the ugly patches though, unless someone really >> wants them, https://lkml.org/lkml/2016/12/16/174 has a copy] >> >> On Friday, December 16, 2016 11:56:21 AM CET Arnd Bergmann wrote: >>> I had some fun doing build testing with older gcc versions, building >>> every release from 4.0 through 7.0 and running that on my randconfig >>> setup to see what comes out. >>> >>> First of all, gcc-4.9 and higher is basically warning-free everywhere, >>> although gcc-7 introduces some interesting new warnings (I have started >>> doing patches for those as well). gcc-4.8 is probably good, too, and >>> gcc-4.6 and 4.7 at least don't produce build failures in general, though >>> the level of false-positive warnings increases (we could decide to turn >>> those off for older compilers for build test purposes). >>> >>> In gcc-4.5 and below, dead code elimination is not as good as later, >>> causing a couple of link errors, and some of them have no good workaround >>> (see patch 1). It would be nice to declare that version too old, but >>> several older distros that are still in wide use ship with compilers >>> earlier than 4.6: >>> >>> RHEL6: gcc-4.4 > > This appears to have support until July 31, 2018. (Though it's using a > 2.6 kernel.) > >>> Debian 6: gcc-4.4 > > This went fully unsupported on Feb 29, 2016. > >>> Ubuntu 10.04: gcc-4.4 > > This went fully unsupported on Apr 30, 2015. > >>> SLES11: gcc-4.3 > > General support ends Mar 31 2019, fully unsupported 31 Mar 2022. (And > like RHEL6 is using a 2.6 kernel.) fyi, SLES11 upgraded to kernel 3.0, in SP2. https://www.novell.com/support/kb/doc.php?id=3594951 Cheers Suzuki