From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755919AbYEZQVA (ORCPT ); Mon, 26 May 2008 12:21:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753164AbYEZQUu (ORCPT ); Mon, 26 May 2008 12:20:50 -0400 Received: from styx.suse.cz ([82.119.242.94]:40865 "EHLO mail.suse.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755373AbYEZQUt (ORCPT ); Mon, 26 May 2008 12:20:49 -0400 Date: Mon, 26 May 2008 18:20:48 +0200 From: Jan Kara To: Ingo Molnar Cc: Theodore Tso , Arjan van de Ven , Linux Kernel Mailing List , Linus Torvalds , Greg KH , Andrew Morton Subject: Re: Top 10 bugs/warnings for the week of March 23rd, 2008 Message-ID: <20080526162048.GH32407@duck.suse.cz> References: <4836EE8C.1010200@linux.intel.com> <20080524222304.GD20563@atrey.karlin.mff.cuni.cz> <20080524153020.1df96cf2@linux.intel.com> <20080524224554.GA5970@mit.edu> <20080526093913.GG13529@elte.hu> <20080526101646.GD24507@mit.edu> <20080526104832.GG23261@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20080526104832.GG23261@elte.hu> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 26-05-08 12:48:32, Ingo Molnar wrote: > > * Theodore Tso wrote: > > > On Mon, May 26, 2008 at 11:39:13AM +0200, Ingo Molnar wrote: > > > Exactly why is pulling an USB stick considered "stupid"? Last i checked > > > there was no physical lock preventing users from doing that. > > > > > > Sure, pulling a mounted USB stick is inconvenient ... for _us_ > > > kernel developers. But the user really doesnt care and shouldnt > > > care. > > > > Because they could lose data? Because if the kernel wakes up and > > tries writing to the USB stick right as they pull it out, it could > > physically damage the flash format? I know, stupid reason... :-) > > user can lose data in many other ways, that's not the issue - the issue > here is something very crutial: the kernel gets confused about a _very_ > common user-triggerable condition. > > That confusion must not happen in a modern OS and the kernel should be > resilient and cope with such external events. And we must not > deprioritize it with an incorrect "user did something stupid" tag... > That argument might have been valid 15 years ago when floppies could be > locked and you needed a needle to force-eject it but it is rather lame > today when unplugging an USB stick is as easy as moving the mouse. > > If there's something stupid here it's the kernel not dealing with that > condition properly. Yes, the "user action" here looks "trivial" to the > user but what happens below is indeed very hard technically, but who > said that writing an OS from scratch would be an easy task? ;-) Well, Ingo, I don't know if you've noticed but the machine continues to run just fine, as far as I understand. It only spits a dangerously looking warning and that's it. I agree we shouldn't be doing this but I don't really find this a critical problem. Honza -- Jan Kara SUSE Labs, CR