Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752593Ab2BZCZZ (ORCPT ); Sat, 25 Feb 2012 21:25:25 -0500 Received: from mx.treblig.org ([80.68.94.177]:57010 "EHLO mx.treblig.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750966Ab2BZCZY (ORCPT ); Sat, 25 Feb 2012 21:25:24 -0500 X-Greylist: delayed 1615 seconds by postgrey-1.27 at vger.kernel.org; Sat, 25 Feb 2012 21:25:24 EST Date: Sun, 26 Feb 2012 01:58:20 +0000 From: "Dr. David Alan Gilbert" To: Mauro Carvalho Chehab Cc: Eduard - Gabriel Munteanu , Jidong Xiao , david@lang.hm, Cong Wang , Kernel development list Subject: Re: Can we move device drivers into user-space? Message-ID: <20120226015820.GB18931@gallifrey> References: <4F4661D6.7030809@gmail.com>

<20120224162109.1bbf157b@redhat.com> <20120225150940.GA3719@localhost> <4F497782.3060902@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4F497782.3060902@redhat.com> X-Chocolate: 70 percent or better cocoa solids preferably X-Operating-System: Linux/2.6.36.4-kvm-i386-20110819 (i686) X-Uptime: 01:44:51 up 21 days, 12:37, 1 user, load average: 0.00, 0.01, 0.05 User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2440 Lines: 47 * Mauro Carvalho Chehab (mchehab@redhat.com) wrote: > Em 25-02-2012 13:10, Eduard - Gabriel Munteanu escreveu: > > On Fri, Feb 24, 2012 at 04:21:09PM -0200, Mauro Carvalho Chehab wrote: > >> Moving a buggy driver to userspace won't fix the bug. You're just moving > >> it from one place to another place. Also, the code will likely require changes > >> to work on userspace, so, the chances are that you're actually introducing more > >> bugs. > > > >> That's said, there are much more eyes inspecting the kernel sources than on any > >> other userspace project. So, the risk of a bad code to be inserted unnoticed at > >> the Linux kernel is degrees of magnitude lower than on an userspace driver. > > > > Those much more eyes have already missed important bugs in the past. > > Yes, nobody is perfect. But the probability that something passes on a 4000+ people > review is lower than the probability of a bug on a piece of code where just one > or two people are looking on it. That there are 4000+ people reading a driver is a big assumption; for common drivers I'd agree - one problem though is there are a lot of drivers for obscure hardware or old/dead hardware/protocols that frankly near to nobody cares about. Very few people read those drivers; yet sometimes they get built and distributed and someone then finds that since no one has looked at them they're full of holes, and given a malicious USB device for example, you can suddenly create one of these devices that only 3 people have bothered to read the source to - 5 years ago. (The Econet security bug recently would be an example of that). There is a line which says that things that really aren't used just shouldn't be built; but then there are things that are only used by a few people, and then ones only used by a few organisations - and it gets very difficult to say at what point you say just turn it off. Dave -- -----Open up your eyes, open up your mind, open up your code ------- / Dr. David Alan Gilbert | Running GNU/Linux | Happy \ \ gro.gilbert @ treblig.org | | In Hex / \ _________________________|_____ http://www.treblig.org |_______/ -- 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/