Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753359AbdFVRtb (ORCPT ); Thu, 22 Jun 2017 13:49:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:54946 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752071AbdFVRta (ORCPT ); Thu, 22 Jun 2017 13:49:30 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E8A422B6A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=luto@kernel.org MIME-Version: 1.0 In-Reply-To: <334e6a92-2d41-c9e1-c807-19e493f1af83@kernel.org> References: <334e6a92-2d41-c9e1-c807-19e493f1af83@kernel.org> From: Andy Lutomirski Date: Thu, 22 Jun 2017 10:49:07 -0700 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: seccomp ptrace selftest failures with 4.4-stable [Was: Re: LTS testing with latest kselftests - some failures] To: Shuah Khan Cc: Kees Cook , Sumit Semwal , Brian Norris , "Luis R. Rodriguez" , Greg Kroah-Hartman , LKML , "# 3.4.x" , "open list:KERNEL SELFTEST FRAMEWORK" , Shuah Khan Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1895 Lines: 40 On Thu, Jun 22, 2017 at 10:09 AM, Shuah Khan wrote: > On 06/22/2017 10:53 AM, Kees Cook wrote: >> On Thu, Jun 22, 2017 at 9:18 AM, Sumit Semwal wrote: >>> Hi Kees, Andy, >>> >>> On 15 June 2017 at 23:26, Sumit Semwal wrote: >>>> 3. 'seccomp ptrace hole closure' patches got added in 4.7 [3] - >>>> feature and test together. >>>> - This one also seems like a security hole being closed, and the >>>> 'feature' could be a candidate for stable backports, but Arnd tried >>>> that, and it was quite non-trivial. So perhaps we'll need some help >>>> from the subsystem developers here. >>> >>> Could you please help us sort this out? Our goal is to help Greg with >>> testing stable kernels, and currently the seccomp tests fail due to >>> missing feature (seccomp ptrace hole closure) getting tested via >>> latest kselftest. >>> >>> If you feel the feature isn't a stable candidate, then could you >>> please help make the test degrade gracefully in its absence? >> >> I don't really want to have that change be a backport -- it's quite >> invasive across multiple architectures. >> >> I would say just add a kernel version check to the test. This is >> probably not the only selftest that will need such things. :) > > Adding release checks to selftests is going to problematic for maintenance. > Tests should fail gracefully if feature isn't supported in older kernels. > > Several tests do that now and please find a way to check for dependencies > and feature availability and fail the test gracefully. If there is a test > that can't do that for some reason, we can discuss it, but as a general > rule, I don't want to see kselftest patches that check release. If a future kernel inadvertently loses the new feature and degrades to the behavior of old kernels, that would be a serious bug and should be caught. --Andy