From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oleg Nesterov Subject: Re: [PATCH v5 1/2] kernel/signal: Signal-based pre-coredump notification Date: Fri, 30 Nov 2018 13:03:45 +0100 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 Return-path: Content-Disposition: inline In-Reply-To: <20181129115520.GO3505@e103592.cambridge.arm.com> Sender: linux-kernel-owner@vger.kernel.org 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 List-Id: linux-arch.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. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 Date: Fri, 30 Nov 2018 13:03:45 +0100 From: Oleg Nesterov 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> Sender: linux-arch-owner@vger.kernel.org List-ID: 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 Message-ID: <20181130120345.yXMoGAAfZA7y04NDGTCqRVfwJ4XfnN8usQTd_pQkhCQ@z> 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.