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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 1ECA4C04EB8 for ; Fri, 30 Nov 2018 12:03:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E3AA721473 for ; Fri, 30 Nov 2018 12:03:55 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E3AA721473 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.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 S1727149AbeK3XM5 (ORCPT ); Fri, 30 Nov 2018 18:12:57 -0500 Received: from mx1.redhat.com ([209.132.183.28]:58668 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726473AbeK3XM5 (ORCPT ); Fri, 30 Nov 2018 18:12:57 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 1825D3001FCB; Fri, 30 Nov 2018 12:03:53 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.43.17.12]) by smtp.corp.redhat.com (Postfix) with SMTP id 50713104C53F; Fri, 30 Nov 2018 12:03:45 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Fri, 30 Nov 2018 13:03:52 +0100 (CET) Date: Fri, 30 Nov 2018 13:03:45 +0100 From: Oleg Nesterov To: Dave Martin Cc: Enke Chen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Peter Zijlstra , Arnd Bergmann , "Eric W. Biederman" , Khalid Aziz , Kate Stewart , Helge Deller , Greg Kroah-Hartman , Al Viro , Andrew Morton , Christian Brauner , Catalin Marinas , Will Deacon , Mauro Carvalho Chehab , Michal Hocko , Rik van Riel , "Kirill A. Shutemov" , Roman Gushchin , Marcos Paulo de Souza , Dominik Brodowski , Cyrill Gorcunov , Yang Shi , Jann Horn , Kees Cook , "linux-kernel@vger.kernel.org" , "linux-arch@vger.kernel.org" , "Victor Kamensky (kamensky)" , "xe-linux-external@cisco.com" , Stefan Strogin Subject: Re: [PATCH v5 1/2] kernel/signal: Signal-based pre-coredump notification Message-ID: <20181130120344.GA25998@redhat.com> References: <7741efa7-a3f8-62a1-ba52-613883164643@cisco.com> <84460a77-a111-404e-4bad-88104a6e246e@cisco.com> <20181026082812.GA10581@redhat.com> <21f678a8-4001-df36-c26e-e96cf203b1b1@cisco.com> <20181029111804.GA24820@redhat.com> <0c197608-3b7e-ffd1-8943-801a60beb917@cisco.com> <80e96710-f424-9b39-72ee-9cc7cbe7a5f7@cisco.com> <20181128151911.GN3505@e103592.cambridge.arm.com> <20181129115520.GO3505@e103592.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181129115520.GO3505@e103592.cambridge.arm.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.43]); Fri, 30 Nov 2018 12:03:54 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 11/29, Dave Martin wrote: > > SIGCHLD + wait() is immune to this problem for other child status > notifications (albeit with higher overhead). > > Unless I've missed something fundamental, signals simply aren't a > reliable data transport Yes. But I hope we are not going to implement WCOREDUMP. I am not fan of this patch, but at least it is simple. Oleg.