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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 94CA9C7618B for ; Thu, 25 Jul 2019 10:16:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 522052081B for ; Thu, 25 Jul 2019 10:16:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389919AbfGYKQb (ORCPT ); Thu, 25 Jul 2019 06:16:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36280 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726738AbfGYKQb (ORCPT ); Thu, 25 Jul 2019 06:16:31 -0400 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id EB1B4756; Thu, 25 Jul 2019 10:16:30 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.136]) by smtp.corp.redhat.com (Postfix) with SMTP id D97C561F21; Thu, 25 Jul 2019 10:16:27 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Thu, 25 Jul 2019 12:16:30 +0200 (CEST) Date: Thu, 25 Jul 2019 12:16:27 +0200 From: Oleg Nesterov To: Christian Brauner Cc: linux-kernel@vger.kernel.org, arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org, joel@joelfernandes.org, tglx@linutronix.de, tj@kernel.org, dhowells@redhat.com, jannh@google.com, luto@kernel.org, akpm@linux-foundation.org, cyphar@cyphar.com, torvalds@linux-foundation.org, viro@zeniv.linux.org.uk, kernel-team@android.com, linux-api@vger.kernel.org Subject: Re: [PATCH 2/5] pidfd: add pidfd_wait() Message-ID: <20190725101626.GD4707@redhat.com> References: <20190724144651.28272-1-christian@brauner.io> <20190724144651.28272-3-christian@brauner.io> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190724144651.28272-3-christian@brauner.io> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Thu, 25 Jul 2019 10:16:31 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/24, Christian Brauner wrote: > > +SYSCALL_DEFINE6(pidfd_wait, int, pidfd, int __user *, stat_addr, > + siginfo_t __user *, info, struct rusage __user *, ru, > + unsigned int, states, unsigned int, flags) > +{ Oh, I too think that P_PIDFD makes more sense. and could you explain in the changelog why? I am not arguing and if nothing else this is consistent with other pidfd features, but if you are parent/debugger you can't hit the problem with pid-reuse, unless you races with your sub-threads. Oleg.