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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 17DA8C04EB8 for ; Thu, 6 Dec 2018 21:47:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D025420868 for ; Thu, 6 Dec 2018 21:47:09 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D025420868 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=xmission.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726014AbeLFVrI (ORCPT ); Thu, 6 Dec 2018 16:47:08 -0500 Received: from out02.mta.xmission.com ([166.70.13.232]:55062 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725949AbeLFVrI (ORCPT ); Thu, 6 Dec 2018 16:47:08 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1gV1U9-0007R4-K9; Thu, 06 Dec 2018 14:47:05 -0700 Received: from ip68-227-174-240.om.om.cox.net ([68.227.174.240] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1gV1U8-0007rG-U8; Thu, 06 Dec 2018 14:47:05 -0700 From: ebiederm@xmission.com (Eric W. Biederman) To: Christian Brauner Cc: linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, luto@kernel.org, arnd@arndb.de, serge@hallyn.com, jannh@google.com, akpm@linux-foundation.org, oleg@redhat.com, cyphar@cyphar.com, viro@zeniv.linux.org.uk, linux-fsdevel@vger.kernel.org, dancol@google.com, timmurray@google.com, linux-man@vger.kernel.org, keescook@chromium.org, fweimer@redhat.com, tglx@linutronix.de, x86@kernel.org References: <20181206121858.12215-1-christian@brauner.io> <87sgzahf7k.fsf@xmission.com> <875zw6bh2z.fsf@xmission.com> <20181206193017.wpxls5p3zgjd6rv2@brauner.io> <871s6u9z6u.fsf@xmission.com> <20181206213152.gvci7ijr3dokew7w@brauner.io> Date: Thu, 06 Dec 2018 15:46:53 -0600 In-Reply-To: <20181206213152.gvci7ijr3dokew7w@brauner.io> (Christian Brauner's message of "Thu, 6 Dec 2018 22:31:57 +0100") Message-ID: <87o99y72gi.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1gV1U8-0007rG-U8;;;mid=<87o99y72gi.fsf@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=68.227.174.240;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX197I2lOQZMKRcTAyanx2Fb6HkXUcekaDDY= X-SA-Exim-Connect-IP: 68.227.174.240 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH v4] signal: add taskfd_send_signal() syscall X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Christian Brauner writes: >> Your intention is to add the thread case to support pthreads once the >> process case is sorted out. So this is something that needs to be made >> clear. Did I miss how you plan to handle threads? > > Yeah, maybe you missed it in the commit message [2] which is based on a > discussion with Andy [3] and Arnd [4]: Looking at your references I haven't missed it. You are not deciding anything as of yet to keep it simple. Except you are returning EOPNOTSUPP. You are very much intending to do something. Decide. Do you use the flags parameter or is the width of the target depending on the flags. That is fundamental to how the system call and it's extensions work. That is fundamental to my review. Until that is decided. Nacked-by: "Eric W. Biederman" There are a lot of fundamental maintenance issues and you can very easily get them wrong if you are not clear on the job of the file descriptor and the job of the flags argument. I want don't want new crap that we have to abandon that has a nasty set of bugs because no one wanted to think through the system call all of the way and understand the corner cases. Eric