Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750861AbdIQED0 (ORCPT ); Sun, 17 Sep 2017 00:03:26 -0400 Received: from mail-oi0-f67.google.com ([209.85.218.67]:37049 "EHLO mail-oi0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750726AbdIQEDX (ORCPT ); Sun, 17 Sep 2017 00:03:23 -0400 X-Google-Smtp-Source: AOwi7QBBeZc7739q5Y6I/Kjhi7jZjVdBangUIzmxOhVRArG0OOp1tOZ4+zZE5JNEmB3khHaecN+a2g== Subject: Re: [PATCH v3] Make initramfs honor CONFIG_DEVTMPFS_MOUNT To: Christophe LEROY , Michael Ellerman , Stephen Rothwell Cc: sachinp , mhocko@suse.com, peterz@infradead.org, viresh.kumar@linaro.org, Benjamin Tissoires , mingo@kernel.org, lokeshvutla@ti.com, Abdul Haleem , linux-input@vger.kernel.org, thomas.lendacky@amd.com, lauraa@codeaurora.org, keescook@chromium.org, Jiri Kosina , rostedt@goodmis.org, linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk, tglx@linutronix.de, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, tj@kernel.org, Andrew Morton , linuxppc-dev References: <1495700957.9020.43.camel@abdul.in.ibm.com> <8760gp9jjl.fsf@concordia.ellerman.id.au> <20170526072437.46499fbd@canb.auug.org.au> <87a7e82d-0af5-7f9e-6bd6-7e28b238e866@landley.net> <87r2z86ykt.fsf@concordia.ellerman.id.au> <4aa9cb26-f868-0720-e5c8-3c4e08afad20@landley.net> <3ba5ddc7-d1a2-7f54-0a26-0752f3975226@c-s.fr> From: Rob Landley Message-ID: Date: Sat, 16 Sep 2017 23:03:19 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <3ba5ddc7-d1a2-7f54-0a26-0752f3975226@c-s.fr> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2061 Lines: 51 On 09/14/2017 04:17 AM, Christophe LEROY wrote: > Le 14/09/2017 à 01:51, Rob Landley a écrit : >> From: Rob Landley >> >> Make initramfs honor CONFIG_DEVTMPFS_MOUNT, and move >> /dev/console open after devtmpfs mount. >> >> Add workaround for Debian bug that was copied by Ubuntu. > > Is that a bug only for Debian ? Why ? Look down, specifically this bit: >> v2 discussion: >> http://lkml.iu.edu/hypermail/linux/kernel/1705.2/05611.html That's some discussion of version 2 of this patch, which was merged for a while last dev cycle, then backed out again because it triggered the same bug in a number of system init scripts: http://lkml.iu.edu/hypermail/linux/kernel/1705.2/07072.html http://lkml.iu.edu/hypermail/linux/kernel/1705.3/01182.html http://lkml.iu.edu/hypermail/linux/kernel/1705.3/01505.html http://lkml.iu.edu/hypermail/linux/kernel/1705.3/01320.html All of whom copied the broken error "recovery" path from debian. If they checked whether it was already mounted, or didn't _blank_ the /dev directory in response to mounting the exact same filesystem over itself giving -EBUSY, the system would work fine. Heck, if you built a kernel with a static /dev in initramfs and no devtmpfs configured in, the script would break things exactly the same way. The breakage is that script takes a hammer to a perfectly functional /dev directory and then continues the boot with an empty /dev. That's bonkers. > Why should a Debian bug be fixed by a workaround in the mainline kernel ? That was my argument last time, and the answer was "Breaking userspace is bad, mmmkay." Even when userspace is doing something REALLY OBVIOUSLY STUPID and it is _clearly_ their fault, as long as they got there first they've established the status quo and it doesn't matter how silly it is. This was explicitly stated to me here: http://lkml.iu.edu/hypermail/linux/kernel/1705.3/03292.html I.E. don't argue with me, argue with him. :) So, I added a workaround with a printk in hopes of embarassing them into someday fixing it. Rob