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_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C8200C433E0 for ; Fri, 26 Jun 2020 19:03:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A86EA2053B for ; Fri, 26 Jun 2020 19:03:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725811AbgFZTDM (ORCPT ); Fri, 26 Jun 2020 15:03:12 -0400 Received: from cheddar.halon.org.uk ([93.93.131.118]:57656 "EHLO cheddar.halon.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725803AbgFZTDM (ORCPT ); Fri, 26 Jun 2020 15:03:12 -0400 Received: from bsmtp by cheddar.halon.org.uk with local-bsmtp (Exim 4.92) (envelope-from ) id 1jotd0-00030i-E2; Fri, 26 Jun 2020 20:03:10 +0100 Received: from steve by tack.einval.org with local (Exim 4.92) (envelope-from ) id 1jotbC-0005mW-VS; Fri, 26 Jun 2020 20:01:18 +0100 Date: Fri, 26 Jun 2020 20:01:18 +0100 From: Steve McIntyre To: John Johansen Cc: Jann Horn , Greg KH , Sasha Levin , stable , 963493@bugs.debian.org Subject: Re: Repeatable hard lockup running strace testsuite on 4.19.98+ onwards Message-ID: <20200626190118.GA21186@tack.einval.com> References: <20200626113558.GA32542@unset.einval.com> <20200626134132.GB4024297@kroah.com> <20200626165000.GB2950@unset.einval.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-attached: unknown User-Agent: Mutt/1.10.1 (2018-07-13) Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On Fri, Jun 26, 2020 at 10:29:28AM -0700, John Johansen wrote: >On 6/26/20 9:50 AM, Steve McIntyre wrote: >> >> OK, will try that second... >> > >I have not been able to reproduce but > >So looking at linux-4.19.y it looks like >1f8266ff5884 apparmor: don't try to replace stale label in ptrace access check > >was picked without >ca3fde5214e1 apparmor: don't try to replace stale label in ptraceme check > >Both of them are marked as >Fixes: b2d09ae449ced ("apparmor: move ptrace checks to using labels") > >so I would expect them to be picked together. > >ptraceme is potentially updating the task's cred while the access check is >running. > >Try building after picking >ca3fde5214e1 apparmor: don't try to replace stale label in ptraceme check Bingo! With that one change the test suite runs to completion, no lockup. \o/ Thanks guys, I think we've found the cause here. -- Steve McIntyre, Cambridge, UK. steve@einval.com "The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." -- Bertrand Russell