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 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 A4AFDC4338F for ; Sat, 21 Aug 2021 16:47:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A663611C8 for ; Sat, 21 Aug 2021 16:47:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229986AbhHUQsL (ORCPT ); Sat, 21 Aug 2021 12:48:11 -0400 Received: from cloud48395.mywhc.ca ([173.209.37.211]:54514 "EHLO cloud48395.mywhc.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229550AbhHUQsI (ORCPT ); Sat, 21 Aug 2021 12:48:08 -0400 Received: from modemcable064.203-130-66.mc.videotron.ca ([66.130.203.64]:43192 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 1mHU9V-0006l1-GN; Sat, 21 Aug 2021 12:47:25 -0400 Message-ID: <9dfb14c1a9ab686df0eeea553b39246bc5b51ede.camel@trillion01.com> Subject: Re: [PATCH] coredump: Limit what can interrupt coredumps From: Olivier Langlois To: Jens Axboe , Tony Battersby , "Eric W. Biederman" , Oleg Nesterov Cc: Linus Torvalds , Linux Kernel Mailing List , linux-fsdevel , io-uring , Alexander Viro , "Pavel Begunkov>" Date: Sat, 21 Aug 2021 12:47:23 -0400 In-Reply-To: <70526737949ab3ad2d8fc551531d286e0f3d88f4.camel@trillion01.com> References: <87eeda7nqe.fsf@disp2133> <87pmwt6biw.fsf@disp2133> <87czst5yxh.fsf_-_@disp2133> <87y2bh4jg5.fsf@disp2133> <87sg1p4h0g.fsf_-_@disp2133> <20210614141032.GA13677@redhat.com> <87pmwmn5m0.fsf@disp2133> <4d93d0600e4a9590a48d320c5a7dd4c54d66f095.camel@trillion01.com> <8af373ec-9609-35a4-f185-f9bdc63d39b7@cybernetics.com> <9d194813-ecb1-2fe4-70aa-75faf4e144ad@kernel.dk> <0bc38b13-5a7e-8620-6dce-18731f15467e@kernel.dk> <24c795c6-4ec4-518e-bf9b-860207eee8c7@kernel.dk> <05c0cadc-029e-78af-795d-e09cf3e80087@cybernetics.com> <84640f18-79ee-d8e4-5204-41a2c2330ed8@kernel.dk> <70526737949ab3ad2d8fc551531d286e0f3d88f4.camel@trillion01.com> Organization: Trillion01 Inc Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.40.4 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit 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: linux-kernel@vger.kernel.org On Sat, 2021-08-21 at 06:08 -0400, Olivier Langlois wrote: > On Tue, 2021-08-17 at 20:57 -0600, Jens Axboe wrote: > > > > Olivier, I sent a 5.10 version for Nathan, any chance you can test > > this > > one for the current kernels? Basically this one should work for > > 5.11+, > > and the later 5.10 version is just for 5.10. I'm going to send it > > out > > separately for review. > > > > I do think this is the right solution, barring a tweak maybe on > > testing > > notify == TWA_SIGNAL first before digging into the task struct. But > > the > > principle is sound, and it'll work for other users of TWA_SIGNAL as > > well. None right now as far as I can tell, but the live patching is > > switching to TIF_NOTIFY_SIGNAL as well which will also cause issues > > with > > coredumps potentially. > > > Ok, I am going to give it a shot. This solution is probably superior > to > the previous attempt as it does not inject io_uring dependency into > the > coredump module. > > The small extra change that I alluded to in my previous reply will > still be relevant even if we go with your patch... > > I'll come back soon with your patch testing result and my small extra > change that I keep teasing about. > > Greetings, > Jens, your patch doesn't compile with 5.12+. AFAIK, the reason is that JOBCTL_TASK_WORK is gone. Wouldn't just a call to tracehook_notify_signal from do_coredump be enough and backward compatible with every possible stable branches? Greetings,