Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751401AbdFDPJU (ORCPT ); Sun, 4 Jun 2017 11:09:20 -0400 Received: from outpost1.zedat.fu-berlin.de ([130.133.4.66]:44086 "EHLO outpost1.zedat.fu-berlin.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751159AbdFDPJN (ORCPT ); Sun, 4 Jun 2017 11:09:13 -0400 Subject: Re: sparc gcc 7.1 compile issue To: Waldemar Brodkorb References: <20170602091717.GA7452@physik.fu-berlin.de> <20170602.102259.363059784928463769.davem@davemloft.net> <1f8e2488-d051-7688-2d40-089f4acab6ce@physik.fu-berlin.de> <20170602.132809.1754806777743128355.davem@davemloft.net> <20170604144044.GK26922@waldemar-brodkorb.de> Cc: David Miller , linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org From: John Paul Adrian Glaubitz Message-ID: Date: Sun, 4 Jun 2017 17:09:10 +0200 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: <20170604144044.GK26922@waldemar-brodkorb.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Originating-IP: 87.77.146.231 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1681 Lines: 48 Hi Waldemar! On 06/04/2017 04:40 PM, Waldemar Brodkorb wrote: >> So, in your point of view it's perfectly fine if an application is able >> to crash the whole kernel with just user privileges? >> >> Shouldn't the kernel be able to cope with that? > > I think he means your kernel you are running might be miscompiled > with gcc 7.1. The kernel wasn't compiled by 7.1. It was built with 6.3: [ 0.000000] PROMLIB: Sun IEEE Boot Prom 'OBP 4.38.8 2017/02/22 13:51' [ 0.000000] PROMLIB: Root node compatible: sun4v [ 0.000000] Linux version 4.12.0-rc1-sparc64-smp (debian-kernel@lists.debian.org) (gcc version 6.3.0 20170510 (Debian 6.3.0-17) ) #1 SMP Debian 4.12~rc1-1~exp1~sparc64 (2017-05-17) > What kernel version you are running? This has been haunting us since around kernel 4.6 or so. It also only shows when building with many parallel jobs. > Which compiler you used to generate the running kernel? 6.3.0 20170510 from the gcc-6 branch. > If it is gcc 7.1, what is if you try to > reproduce the crash with the same kernel version compiled with gcc > 6.3? It's simply gcc-7's testsuite that's crashing the kernel since kernel versions around 4.6. We haven't done any kernel compiles with gcc-7.1 yet since gcc-7.1 not yet the default compiler, we're just building the package in Debian experimental. > Wouldn't this show if it is a compiler or kernel bug? Yes and I think the data suggests it's rather a kernel bug than a bug in gcc. Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaubitz@debian.org `. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913