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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 10A7CC43334 for ; Sat, 16 Jul 2022 21:31:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230379AbiGPVb3 (ORCPT ); Sat, 16 Jul 2022 17:31:29 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229619AbiGPVb2 (ORCPT ); Sat, 16 Jul 2022 17:31:28 -0400 Received: from out01.mta.xmission.com (out01.mta.xmission.com [166.70.13.231]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 397D255A7 for ; Sat, 16 Jul 2022 14:31:28 -0700 (PDT) Received: from in02.mta.xmission.com ([166.70.13.52]:53112) by out01.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1oCpNl-003XHC-Sw; Sat, 16 Jul 2022 15:31:25 -0600 Received: from ip68-227-174-4.om.om.cox.net ([68.227.174.4]:48014 helo=email.froward.int.ebiederm.org.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1oCpNk-0096qh-SE; Sat, 16 Jul 2022 15:31:25 -0600 From: "Eric W. Biederman" To: Keno Fischer Cc: Linux Kernel Mailing List , mingo@kernel.org, Sebastian Andrzej Siewior , Peter Zijlstra , Jann Horn , Kees Cook , Alexander Gordeev , "Robert O'Callahan" , Kyle Huey , Oleg Nesterov References: <20220421150248.667412396@infradead.org> <20220421150654.817117821@infradead.org> <87czhap9dy.fsf@email.froward.int.ebiederm.org> <878rrrh32q.fsf_-_@email.froward.int.ebiederm.org> <87k0b7v9yk.fsf_-_@email.froward.int.ebiederm.org> <87k0b0apne.fsf_-_@email.froward.int.ebiederm.org> <87a6bv6dl6.fsf_-_@email.froward.int.ebiederm.org> <87r13gd4xy.fsf_-_@email.froward.int.ebiederm.org> <87edyvgs2s.fsf@email.froward.int.ebiederm.org> <875yk22j5z.fsf@email.froward.int.ebiederm.org> Date: Sat, 16 Jul 2022 16:29:49 -0500 In-Reply-To: <875yk22j5z.fsf@email.froward.int.ebiederm.org> (Eric W. Biederman's message of "Tue, 12 Jul 2022 15:03:04 -0500") Message-ID: <87pmi4ycdu.fsf@email.froward.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1oCpNk-0096qh-SE;;;mid=<87pmi4ycdu.fsf@email.froward.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.174.4;;;frm=ebiederm@xmission.com;;;spf=softfail X-XM-AID: U2FsdGVkX1+/Vjcg1LG+PkIixgXe8YCIN4VRwU6Ap+E= X-SA-Exim-Connect-IP: 68.227.174.4 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 0/3] ptrace: Stop supporting SIGKILL for PTRACE_EVENT_EXIT X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "Eric W. Biederman" writes: > Keno Fischer writes: > >> Hi Eric, >> >> On Fri, Jul 8, 2022 at 6:25 PM Eric W. Biederman wrote: >>> > Recently I had a conversation where it was pointed out to me that >>> > SIGKILL sent to a tracee stropped in PTRACE_EVENT_EXIT is quite >>> > difficult for a tracer to handle. >>> > >>> >>> RR folks any comments? >>> >>> Did I properly understand what Keno Fischer was asking for when we >>> talked in person? >> >> Yes, this is indeed what I had in mind. I have not yet had the opportunity >> to try out your patch series (sorry), but from visual inspection, it does indeed >> do what I wanted, which is to make sure that a tracee stays in >> PTRACE_EVENT_EXIT for the tracer to inspect, even if there is another >> SIGKILL incoming simultaneously (since otherwise it may be impossible >> for the tracer to observe the PTRACE_EVENT_EXIT if two SIGKILLs >> come in rapid succession). I will try to take this series for a proper spin >> shortly. > > Thanks, > > I haven't yet figured out how to get the rr test suite to run > successfully. Something about my test machine and lack of perf counters > seems to be causing problems. So if you can perform the testing on your > side that would be fantastic. Ok. I finally found a machine where I can run rr and the rr test suite. It looks like there are a couple of the rr 5.5.0 test that fail on Linus's lastest kernel simply because of changes in kernel behavior. In particular clone_cleartid_coredump, and fcntl_rw_hints. The clone_cleartid_coredump appears to fail because SIGSEGV no longer kills all processes that share an mm. Which was a deliberate change. With the lastest development version of rr, only detach_sigkill appears to be failing on Linus's latest. That failure appears to be independent of the patches in question as well. When run manually the detach_sigkill test succeeds so I am not quite certain what is going on, any thoughts? As for my patchset it looks like it does not cause any new test failures for rr so I will plan on getting it into linux-next shortly. Eric