Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753557AbZIQU0g (ORCPT ); Thu, 17 Sep 2009 16:26:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752919AbZIQU0d (ORCPT ); Thu, 17 Sep 2009 16:26:33 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:56912 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752787AbZIQU0d (ORCPT ); Thu, 17 Sep 2009 16:26:33 -0400 Date: Thu, 17 Sep 2009 13:26:01 -0700 (PDT) From: Linus Torvalds X-X-Sender: torvalds@localhost.localdomain To: Kay Sievers cc: Ingo Molnar , "Eric W. Biederman" , Greg KH , linux-kernel@vger.kernel.org Subject: Re: [bug] /etc/profile: line 30: /dev/null: Permission denied (Was: Re: [PATCH] Remove broken by design and by implementation devtmpfs maintenance disaster) In-Reply-To: Message-ID: References: <20090917125759.GA4045@kroah.com> <20090917185306.GA28635@elte.hu> User-Agent: Alpine 2.01 (LFD 1184 2008-12-16) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1791 Lines: 43 On Thu, 17 Sep 2009, Kay Sievers wrote: > On Thu, Sep 17, 2009 at 20:53, Ingo Molnar wrote: > > I've reproduced a bug with the following .config options: > > > >  CONFIG_DEVTMPFS=y > >  CONFIG_DEVTMPFS_MOUNT=y > > > > /dev/null and /dev/zero are not read/writable to ordinary users, > > breaking normal bootup and login: > > Udev should run long before some ordinary/non-root user can login, and > apply the permissions as it always does. It's known to work on Fedora, > SUSE, Ubuntu. What kind of system/environment/setup is that where you > see this? I don't know if this is what Ingo does, but I have a few machines where I don't run the distro-supplied 'initrd' at all, because it's easier to boot without it. The Fedora initrd doesn't allow me to sanely set root filesystem parameters without totally rewriting the initrd image, which I'm not interested in, for example (they'll take effect for the root initrd, not the final root). That may be "not supported", but the point is, we want to make the kernel be as self-sufficient as possible, and the whole _point_ of this devtmpfs seemed to be to increase self-sufficiency rather than decrease it by requiring 'udev' to have run very very early. If you have udev running really early, then what's the point of devtmpfs? You might as well just have udev and tmpfs. So I suspect /dev/null and /dev/zero should be special - just make them have 0666 permissions. Because they really _are_ special, and no other permissions ever make sense for them. Linus -- 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/