From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758334AbZBEJDf (ORCPT ); Thu, 5 Feb 2009 04:03:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756166AbZBEJCt (ORCPT ); Thu, 5 Feb 2009 04:02:49 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:53064 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755620AbZBEJCs (ORCPT ); Thu, 5 Feb 2009 04:02:48 -0500 Date: Thu, 5 Feb 2009 10:02:29 +0100 From: Pavel Machek To: Christoph Hellwig , Eric Sesterhenn , Chris Mason , linux-kernel@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: Re: Warning and BUG with btrfs and corrupted image Message-ID: <20090205090229.GA2011@elf.ucw.cz> References: <20090120101119.GB10158@disturbed> <20090120101503.GC17377@alice> <20090120125944.GC10158@disturbed> <20090120132829.GA27429@infradead.org> <20090120222019.GB2320@elf.ucw.cz> <20090121040042.GI10158@disturbed> <20090126162711.GA2083@elf.ucw.cz> <20090201014050.GD24173@disturbed> <20090204182951.GC4797@elf.ucw.cz> <20090205085916.GP24173@disturbed> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090205085916.GP24173@disturbed> X-Warning: Reading this can be dangerous to your mental health. User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > > CONFIG_*_DEBUG means include *debug* code there to help developers, > > > including adding additional failure tests into the kernel. Besides, > > > which bit of "don't turn it on unless you are an XFS developer" > > > don't you understand? > > > > Yes, but DEBUG code is normally to help debugging, not to crash > > kernels. > > Crashing the kernel at exactly the point a problem is detected > is often the simplest way of debugging the problem. > > e.g. CONFIG_VM_DEBUG=y turns on VM_BUG_ON() which crashes the kernel > whenever it detects something wrong. Do I turn it on? Yes. Do i That's different. User is not supposed to be able to trigger VM_BUG_ON(). > complain about it when I hit a VM_BUG_ON()? No, I report the > bug and move on. If you turn on a DEBUG option, then you are > asking the system to behave in a way useful to a developer, > not an end user. That includes panicing when something wrong > is detected. Imagine vm going panic() on mkdir("/lost+found")... Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html