Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760587AbXEYKLx (ORCPT ); Fri, 25 May 2007 06:11:53 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753149AbXEYKLp (ORCPT ); Fri, 25 May 2007 06:11:45 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:59545 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752624AbXEYKLn (ORCPT ); Fri, 25 May 2007 06:11:43 -0400 X-Greylist: delayed 52379 seconds by postgrey-1.27 at vger.kernel.org; Fri, 25 May 2007 06:11:43 EDT Date: Fri, 25 May 2007 12:11:05 +0200 From: Ingo Molnar To: Linus Torvalds Cc: Christoph Lameter , Michal Piotrowski , Andrew Morton , LKML , "Cherwin R. Nooitmeer" , linux-pcmcia@lists.infradead.org, Robert de Rooy , Alan Cox , Tejun Heo , sparclinux@vger.kernel.org, David Miller , Mikael Pettersson , linux1394-devel@lists.sourceforge.net, Stefan Richter , Kristian H?gsberg , linux-pm@lists.linux-foundation.org, "Rafael J. Wysocki" , Pavel Machek , Marcus Better , Andrey Borzenkov , linux-usb-devel@lists.sourceforge.net, Greg Kroah-Hartman Subject: Re: [2/3] 2.6.22-rc2: known regressions v2 Message-ID: <20070525101105.GA9268@elte.hu> References: <46558708.2040803@googlemail.com> <46559B54.80106@googlemail.com> <20070524193740.GA6787@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.0.3 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2122 Lines: 47 * Linus Torvalds wrote: > > i very much agree that this kmalloc_index() one shouldnt be called a > > "BUG: ", but if you look at the majority of WARN_ON() instances they > > are checks for clear, serious kernel bugs. > > I _still_ disagree. > > There's a huge difference between "You killed my father, prepare to > die", and "Btw, I didn't like that, but I'll just continue". yeah ... > And that's the difference between BUG_ON() and WARN_ON(). how about this solution: make WARN_ON() a "WARNING: " like you suggested (i still agree with that in principle), but also solve the additional problem i'm trying to outline: make BUG_ON() _not_ crash the box [only if the user asks for a crash to happen in such circumstances - this can be a sysctl.]. Then i can change the majority of the current WARN_ON()s to BUG_ON()s. Most of the WARN_ON()s i personally add (and most of the WARN_ON()s i see others adding) are not WARN_ON()s because "i didnt like that and i'll just continue", they are WARN_ON() because i want _actual feedback from users_. A BUG_ON() has a (much) lower likelyhood of being reported back - for most users it is a "X just hung hard, there was nothing in the syslog, i had to switch back to the older kernel" experience, and they do not have a serial console to hook up (newer hardware often doesnt even have a serial port). With the WARN_ON()s we have a _chance_ that despite the seriousness of the bug, the message makes it to the syslog, until the system comes to a screeching halt due to side-effects of the bug. in that sense i am part of the problem: i was adding WARN_ON()s that werent true 'warnings' but 'bugs'. So i'd very much like to fix that problem, but i'd also like to solve the (very serious and existing) problem of BUG_ON()s making it less likely to get bugs reported back. Ingo - 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/