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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 68F37C47094 for ; Thu, 10 Jun 2021 15:17:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 51709613F8 for ; Thu, 10 Jun 2021 15:17:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231615AbhFJPTL (ORCPT ); Thu, 10 Jun 2021 11:19:11 -0400 Received: from cloud48395.mywhc.ca ([173.209.37.211]:59412 "EHLO cloud48395.mywhc.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231625AbhFJPTK (ORCPT ); Thu, 10 Jun 2021 11:19:10 -0400 Received: from modemcable064.203-130-66.mc.videotron.ca ([66.130.203.64]:51970 helo=[192.168.1.179]) by cloud48395.mywhc.ca with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.94.2) (envelope-from ) id 1lrMQi-0002Ys-MC; Thu, 10 Jun 2021 11:17:12 -0400 Message-ID: <274c764afe34abdf06abc6a7eaf753a2911c967b.camel@trillion01.com> Subject: Re: [RFC] coredump: Do not interrupt dump for TIF_NOTIFY_SIGNAL From: Olivier Langlois To: "Eric W. Biederman" Cc: Linus Torvalds , Linux Kernel Mailing List , linux-fsdevel , io-uring , Alexander Viro , Jens Axboe , "Pavel Begunkov>" , Oleg Nesterov Date: Thu, 10 Jun 2021 11:17:11 -0400 In-Reply-To: <87pmwt6biw.fsf@disp2133> References: <192c9697e379bf084636a8213108be6c3b948d0b.camel@trillion01.com> <9692dbb420eef43a9775f425cb8f6f33c9ba2db9.camel@trillion01.com> <87h7i694ij.fsf_-_@disp2133> <198e912402486f66214146d4eabad8cb3f010a8e.camel@trillion01.com> <87eeda7nqe.fsf@disp2133> <87pmwt6biw.fsf@disp2133> Organization: Trillion01 Inc Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.40.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - cloud48395.mywhc.ca X-AntiAbuse: Original Domain - vger.kernel.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - trillion01.com X-Get-Message-Sender-Via: cloud48395.mywhc.ca: authenticated_id: olivier@trillion01.com X-Authenticated-Sender: cloud48395.mywhc.ca: olivier@trillion01.com X-Source: X-Source-Args: X-Source-Dir: Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, 2021-06-10 at 09:26 -0500, Eric W. Biederman wrote: > Olivier Langlois writes: > > > On Wed, 2021-06-09 at 16:05 -0500, Eric W. Biederman wrote: > > > > > > > > So the TIF_NOTIFY_SIGNAL does get set WHILE the core dump is > > > > written. > > > > > > Did you mean? > > > > > > So the TIF_NOTIFY_SIGNAL does _not_ get set WHILE the core dump > > > is > > > written. > > > > > > > > Absolutely not. I did really mean what I have said. Bear with me > > that, > > I am not qualifying myself as an expert kernel dev yet so feel free > > to > > correct me if I say some heresy... > > No.  I was just asking to make certain I understood what you said. > > I thought you said you were getting a consistent 0 byte coredump, > and that implied that TIF_NOTIFY_SIGNAL was coming in before > the coredump even started. due to the asynchronous nature of the problem, it is all random. Sometimes, I do get 0 byte coredump. Most of the times, I get a truncated one and very rarely (this is why the issue was so annoying), I get a full coredump. > > So I will spin up a good version of my patch (based on your patch) > so we can unbreak coredumps. > That is super nice. I am looking forward it! Greetings, Olivier