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=-0.8 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 A26BCC0044C for ; Wed, 31 Oct 2018 05:01:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 51BB220685 for ; Wed, 31 Oct 2018 05:01:40 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 51BB220685 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 S1729167AbeJaN6G (ORCPT ); Wed, 31 Oct 2018 09:58:06 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:43247 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728978AbeJaN6F (ORCPT ); Wed, 31 Oct 2018 09:58:05 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.87) (envelope-from ) id 1gHidM-0000hB-Ne; Tue, 30 Oct 2018 23:01:36 -0600 Received: from 67-3-154-154.omah.qwest.net ([67.3.154.154] 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 1gHid7-0001Z2-Cf; Tue, 30 Oct 2018 23:01:36 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Christian Brauner Cc: Daniel Colascione , Joel Fernandes , Linux Kernel Mailing List , Tim Murray , Suren Baghdasaryan References: <20181029221037.87724-1-dancol@google.com> <20181030103910.mnzot3zcoh6j7did@gmail.com> <20181030104037.73t5uz3piywxwmye@gmail.com> Date: Wed, 31 Oct 2018 00:00:51 -0500 In-Reply-To: (Christian Brauner's message of "Tue, 30 Oct 2018 12:19:51 +0100") Message-ID: <87h8h21zi4.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=1gHid7-0001Z2-Cf;;;mid=<87h8h21zi4.fsf@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=67.3.154.154;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18ocbg7AB8i1EGx2q5vpV3n5aF+D6ZRGTs= X-SA-Exim-Connect-IP: 67.3.154.154 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [RFC PATCH] Implement /proc/pid/kill 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: > On Tue, Oct 30, 2018 at 12:12 PM Daniel Colascione wrote: >> >> On Tue, Oct 30, 2018 at 11:04 AM, Christian Brauner >> wrote: >> > On Tue, Oct 30, 2018 at 11:48 AM Daniel Colascione wrote: >> >> >> >> Why not? >> >> >> >> Does your proposed API allow for a race-free pkill, with arbitrary >> >> selection criteria? This capability is a good litmus test for fixing >> >> the long-standing Unix process API issues. >> > >> > You'd have a handle on the process with an fd so yes, it would be. >> >> Thanks. That's good to hear. >> >> Any idea on the timetable for this proposal? I'm open to lots of >> alternative technical approaches, but I don't want this capability to >> languish for a long time. > > Latest end of year likely sooner depending on the feedback I'm getting > during LPC. Frankly. If you want a race free fork variant probably the easiest thing to do is to return a open copy of the proc directory entry. Wrapped in a bind mount so that you can't see beyond that directory in proc. My only concern would be if a vfsmount per process would be too heavy for such a use. Eric