From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 678C9C4338F for ; Sat, 14 Aug 2021 02:05:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3E8B860FC3 for ; Sat, 14 Aug 2021 02:05:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236284AbhHNCF6 (ORCPT ); Fri, 13 Aug 2021 22:05:58 -0400 Received: from zeniv-ca.linux.org.uk ([142.44.231.140]:54920 "EHLO zeniv-ca.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232651AbhHNCF5 (ORCPT ); Fri, 13 Aug 2021 22:05:57 -0400 Received: from viro by zeniv-ca.linux.org.uk with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1mEj0c-00BTXs-As; Sat, 14 Aug 2021 02:02:50 +0000 Date: Sat, 14 Aug 2021 02:02:50 +0000 From: Al Viro To: Linus Torvalds Cc: Andy Lutomirski , "Eric W. Biederman" , David Laight , David Hildenbrand , Linux Kernel Mailing List , Andrew Morton , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Alexey Dobriyan , Steven Rostedt , "Peter Zijlstra (Intel)" , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Sergey Senozhatsky , Andy Shevchenko , Rasmus Villemoes , Kees Cook , Greg Ungerer , Geert Uytterhoeven , Mike Rapoport , Vlastimil Babka , Vincenzo Frascino , Chinwen Chang , Michel Lespinasse , Catalin Marinas , "Matthew Wilcox (Oracle)" , Huang Ying , Jann Horn , Feng Tang , Kevin Brodsky , Michael Ellerman , Shawn Anastasio , Steven Price , Nicholas Piggin , Christian Brauner , Jens Axboe , Gabriel Krisman Bertazi , Peter Xu , Suren Baghdasaryan , Shakeel Butt , Marco Elver , Daniel Jordan , Nicolas Viennot , Thomas Cedeno , Collin Fijalkovich , Michal Hocko , Miklos Szeredi , Chengguang Xu , Christian =?iso-8859-1?Q?K=F6nig?= , "linux-unionfs@vger.kernel.org" , Linux API , the arch/x86 maintainers , "" , Linux-MM , Florian Weimer , Michael Kerrisk Subject: Re: [PATCH v1 0/7] Remove in-tree usage of MAP_DENYWRITE Message-ID: References: <87lf56bllc.fsf@disp2133> <87eeay8pqx.fsf@disp2133> <5b0d7c1e73ca43ef9ce6665fec6c4d7e@AcuMS.aculab.com> <87h7ft2j68.fsf@disp2133> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: Al Viro Precedence: bulk List-ID: X-Mailing-List: linux-unionfs@vger.kernel.org On Sat, Aug 14, 2021 at 01:57:31AM +0000, Al Viro wrote: > On Fri, Aug 13, 2021 at 02:58:57PM -1000, Linus Torvalds wrote: > > On Fri, Aug 13, 2021 at 2:54 PM Linus Torvalds > > wrote: > > > > > > And nobody really complained when we weakened it, so maybe removing it > > > entirely might be acceptable. > > > > I guess we could just try it and see... Worst comes to worst, we'll > > have to put it back, but at least we'd know what crazy thing still > > wants it.. > > Umm... I'll need to go back and look through the thread, but I'm > fairly sure that there used to be suckers that did replacement of > binary that way (try to write, count on exclusion with execve while > it's being written to) instead of using rename. Install scripts > of weird crap and stuff like that... ... and before anyone goes off - I certainly agree that using that behaviour is not a good idea and had never been one. All I'm saying is that there at least used to be very random (and rarely exercised) bits of userland relying upon that behaviour.