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=-3.9 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 7965CC47420 for ; Wed, 23 Sep 2020 07:53:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 34E512371F for ; Wed, 23 Sep 2020 07:53:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=suse.com header.i=@suse.com header.b="er+muJI7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726332AbgIWHxe (ORCPT ); Wed, 23 Sep 2020 03:53:34 -0400 Received: from mx2.suse.de ([195.135.220.15]:41266 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726210AbgIWHxc (ORCPT ); Wed, 23 Sep 2020 03:53:32 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1600847610; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=CuHUMp2i3TRP7V8scoazcWiRgaPQjjBjBbbJZmwakt8=; b=er+muJI71Xard5EO7GqXt1gwtHwqYgVtxN6WAIy2EocdMMAYI7jTm8vyYdPCK8zXvHzxUm 84lqDh/YaVIQPW29KGk24fGId98opcrqh6ac1oxf+24m6mHUwGSOiA79xdf7/7OjRdnTHD c/47TeDNosuJJW0DFDqYNU5ajsqHL8c= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id BE171AE0D; Wed, 23 Sep 2020 07:54:07 +0000 (UTC) Date: Wed, 23 Sep 2020 09:53:29 +0200 From: Michal Hocko To: Christian Brauner Cc: Tejun Heo , Peter Xu , Linus Torvalds , Jason Gunthorpe , John Hubbard , Leon Romanovsky , Linux-MM , Linux Kernel Mailing List , "Maya B . Gokhale" , Yang Shi , Marty Mcfadden , Kirill Shutemov , Oleg Nesterov , Jann Horn , Jan Kara , Kirill Tkhai , Andrea Arcangeli , Christoph Hellwig , Andrew Morton Subject: Re: [PATCH 1/4] mm: Trial do_wp_page() simplification Message-ID: <20200923075329.GC4887@dhcp22.suse.cz> References: <20200918164032.GA5962@xz-x1> <20200921134200.GK12990@dhcp22.suse.cz> <20200921141830.GE5962@xz-x1> <20200921142834.GL12990@dhcp22.suse.cz> <20200921143847.GB4268@mtj.duckdns.org> <20200921144355.mrzc66lina3dkfjq@wittgenstein> <20200921145537.GM12990@dhcp22.suse.cz> <20200921150450.3mjjb3p3jwgatn4v@wittgenstein> <20200921160643.GP12990@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200921160643.GP12990@dhcp22.suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon 21-09-20 18:06:44, Michal Hocko wrote: [...] > Thanks a lot for this clarification! So I believe the only existing bug > is in documentation which should be explicit that the cgroup fd read > access is not sufficient because it also requires to have a write access > for cgroup.procs in the same directory at the time of fork. I will send > a patch if I find some time for that. I have reread the man page and concluded that the current wording is not bugy. It is referring to cgroups(7) which has all the information but it takes quite some to drill down to the important point. On the other hand there are many details (like delegation, namespaces) which makes it quite complex to be concise in clone(2) so it is very likely better to leave as it is. -- Michal Hocko SUSE Labs