Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A3F3C433F5 for ; Thu, 9 Dec 2021 15:07:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239154AbhLIPKl (ORCPT ); Thu, 9 Dec 2021 10:10:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42278 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232856AbhLIPKk (ORCPT ); Thu, 9 Dec 2021 10:10:40 -0500 Received: from sin.source.kernel.org (sin.source.kernel.org [IPv6:2604:1380:40e1:4800::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9B6D2C061746 for ; Thu, 9 Dec 2021 07:07:06 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by sin.source.kernel.org (Postfix) with ESMTPS id 55BB8CE2644 for ; Thu, 9 Dec 2021 15:07:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55438C004DD; Thu, 9 Dec 2021 15:06:58 +0000 (UTC) Date: Thu, 9 Dec 2021 16:06:55 +0100 From: Christian Brauner To: Michal =?utf-8?Q?Koutn=C3=BD?= Cc: Tejun Heo , Linus Torvalds , "Eric W. Biederman" , Linux Kernel Mailing List , Jens Axboe , Kees Cook , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Jim Newsome , Alexey Gladkov , Security Officers , Andy Lutomirski , Jann Horn Subject: Re: [PATCH] exit: Retain nsproxy for exit_task_work() work entries Message-ID: <20211209150655.zqm77gmteu436xvb@wittgenstein> References: <20211208180501.11969-1-mkoutny@suse.com> <87sfv3540t.fsf@email.froward.int.ebiederm.org> <20211209134419.GA17186@blackbody.suse.cz> <20211209140826.kc2xvvwxrdrwmrtj@wittgenstein> <20211209144700.GC63648@blackbody.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211209144700.GC63648@blackbody.suse.cz> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 09, 2021 at 03:47:00PM +0100, Michal Koutný wrote: > On Thu, Dec 09, 2021 at 03:08:26PM +0100, Christian Brauner wrote: > > send_sig() isn't used that was changed in response to a review. I'm > > confused. > > Sorry for ambiguity, I meant this instance [1]. Sure, seems good. > > > Kill and freeze only do time permission checking at open. Why would you > > introduce another write time check? > > Let's have a cgroup G with tasks t1,...,tn (run by user u) and some > monitoring tasks m1,...,mk belonging to a different user v != u. > > Currently u can kill also the tasks of v -- I'm not sure if that's > intentional. My argument would apply if it wasn't -- it'd be suscebtible That was discussed and is intentional and is supposed to mirror the behavior of cgroup.freeze. Delegated killing was supposed to work and was one use-case.