Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752752AbbFHInU (ORCPT ); Mon, 8 Jun 2015 04:43:20 -0400 Received: from h1446028.stratoserver.net ([85.214.92.142]:35481 "EHLO mail.ahsoftware.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751735AbbFHInK (ORCPT ); Mon, 8 Jun 2015 04:43:10 -0400 Message-ID: <5575558E.5070706@ahsoftware.de> Date: Mon, 08 Jun 2015 10:42:54 +0200 From: Alexander Holler User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Richard Weinberger CC: Ingo Molnar , Linus Torvalds , Tejun Heo , Louis Langholtz , Linux Kernel Mailing List , Trivial patch monkey , Rusty Russell , Andrew Morton , Peter Zijlstra , Thomas Gleixner Subject: Re: [PATCH] debug: Deprecate BUG_ON() use in new code, introduce CRASH_ON() References: <1433721270-9182-1-git-send-email-lou_langholtz@me.com> <20150608000007.GA3543@mtj.duckdns.org> <20150608071215.GA369@gmail.com> <557546E6.5030304@ahsoftware.de> In-Reply-To: Content-Type: text/plain; charset=utf-8; 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: 1819 Lines: 48 Am 08.06.2015 um 10:08 schrieb Richard Weinberger: > On Mon, Jun 8, 2015 at 9:40 AM, Alexander Holler wrote: >> Am 08.06.2015 um 09:12 schrieb Ingo Molnar: >>> >>> >>> * Linus Torvalds wrote: >>> >>>> Stop with the random BUG_ON() additions. >>> >>> >>> Yeah, so I propose the attached patch which attempts to resist new >>> BUG_ON() >>> additions. >> >> >> As this reminded me at flame I received once from a maintainer because I >> wanted to avoid a desastrous memory corruption by using a BUG_ON(). > > Reference? https://lkml.org/lkml/2013/5/17/254 To explain: The bug already existed for several releases and the memory corruption was that desatrous that it even leaded here to hard resets of systems without any oops. And fixing it needed several more releases (another year). And in the above mentioned case and the kernel config settings I use(d), only the wronggoing thread was killed by the BUG_ON (I proposed) before it had the chance to corrupt the memory. Maybe someone could clarify what Greg meant with "something _really_ bad", because in my humble opionion there aren't much more worse things than memory corruptions (e.g. by wrong pointers, use after free or similiar stuff) if that happens inside the kernel. The consequences of such are almost always unpredictable and therefor I would and likely will ever prefer a controlled shutdown, reset or similiar instead of leaving a system running with corrupted memory. Regardless what any maintainer will say. Regards, Alexander Holler -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/