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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_2 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 8C759C55179 for ; Fri, 30 Oct 2020 10:03:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 33FEE2083B for ; Fri, 30 Oct 2020 10:03:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726285AbgJ3KDa (ORCPT ); Fri, 30 Oct 2020 06:03:30 -0400 Received: from mail-out.m-online.net ([212.18.0.9]:47383 "EHLO mail-out.m-online.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725808AbgJ3KDa (ORCPT ); Fri, 30 Oct 2020 06:03:30 -0400 Received: from frontend01.mail.m-online.net (unknown [192.168.8.182]) by mail-out.m-online.net (Postfix) with ESMTP id 4CMyYr3Vlvz1qsZq; Fri, 30 Oct 2020 11:03:28 +0100 (CET) Received: from localhost (dynscan1.mnet-online.de [192.168.6.70]) by mail.m-online.net (Postfix) with ESMTP id 4CMyYr2Yqhz1qsX6; Fri, 30 Oct 2020 11:03:28 +0100 (CET) X-Virus-Scanned: amavisd-new at mnet-online.de Received: from mail.mnet-online.de ([192.168.8.182]) by localhost (dynscan1.mail.m-online.net [192.168.6.70]) (amavisd-new, port 10024) with ESMTP id nIvhleJi1drz; Fri, 30 Oct 2020 11:03:26 +0100 (CET) X-Auth-Info: gud4iyWn4GyHtz0vQS4y9GXSDNbsg+3/gBpY/WHjLF4= Received: from jawa (85-222-111-42.dynamic.chello.pl [85.222.111.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.mnet-online.de (Postfix) with ESMTPSA; Fri, 30 Oct 2020 11:03:26 +0100 (CET) Date: Fri, 30 Oct 2020 11:02:29 +0100 From: Lukasz Majewski To: Andrei Vagin , Dmitry Safonov , Thomas Gleixner Cc: GNU C Library , Arnd Bergmann , linux-kernel@vger.kernel.org Subject: [Y2038][time namespaces] Question regarding CLOCK_REALTIME support plans in Linux time namespaces Message-ID: <20201030110229.43f0773b@jawa> Organization: denx.de X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; boundary="Sig_/gUM4x0hyt5rpW=rxvYzDQjJ"; protocol="application/pgp-signature" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --Sig_/gUM4x0hyt5rpW=rxvYzDQjJ Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable Hi Andrei, Dmitry, I do have a question regarding the Linux time namespaces in respect of adding support for virtualizing the CLOCK_REALTIME. According to patch description [1] and time_namespaces documentation [2] the CLOCK_REALTIME is not supported (for now?) to avoid complexity and overhead in the kernel. Is there any plan to add support for it in a near future? Why I'm asking?=20 It looks like this kernel feature (with CLOCK_REALTIME support available) would be very helpful for testing Y2038 compliance for e.g. glibc 32 bit ports. To be more specific - it would be possible to modify time after time_t 32 bit overflow (i.e. Y2038 bug) on the process running Y2038 regression tests on the host system (64 bit one). By using Linux time namespaces the system time will not be affected in any way. Thanks in advance for your help. Links: [1] - https://lkml.org/lkml/2019/10/10/1329 [2] - https://www.man7.org/linux/man-pages/man7/time_namespaces.7.html Best regards, Lukasz Majewski -- DENX Software Engineering GmbH, Managing Director: Wolfgang Denk HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-59 Fax: (+49)-8142-66989-80 Email: lukma@denx.de --Sig_/gUM4x0hyt5rpW=rxvYzDQjJ Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQEzBAEBCgAdFiEEgAyFJ+N6uu6+XupJAR8vZIA0zr0FAl+b5LUACgkQAR8vZIA0 zr1a2QgAynsCmxwHIDmCgKM0PFeeoyjn0GKD95l4r4q0uDbbQ5tjwP4nf+MdRW4l 8DPo11i2OKobdU2W+uM4Zs+tLFVa+nRIvOekStIkWoImkhyzLki0TPcYGv8axCD0 33Wow5Z9psNBt0FALbPz1AJA+mjiqHjuKzzSeylB+ZixaK8VexS+j9yprUU9Cdh0 xjDvePVkW5YZm/TuUEonchpfiZ9WuuBqC79tmpLZt+L/ShE0eC755sCKpNGG0/rb Zt6zAQlM7CDnqVYKdBJLqBiSzQLNkX8N+8upDPmlyFjLQzQNvpZptV6EfmhgMYcj 7QSL7fsrEqC350QLcSDDm99weaIXrw== =6zOG -----END PGP SIGNATURE----- --Sig_/gUM4x0hyt5rpW=rxvYzDQjJ--