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=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS autolearn=unavailable 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 8AF21C433E0 for ; Mon, 1 Mar 2021 22:15:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4F144600EF for ; Mon, 1 Mar 2021 22:15:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239302AbhCAWPQ (ORCPT ); Mon, 1 Mar 2021 17:15:16 -0500 Received: from maynard.decadent.org.uk ([95.217.213.242]:60936 "EHLO maynard.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237647AbhCARat (ORCPT ); Mon, 1 Mar 2021 12:30:49 -0500 Received: from [2a02:1811:d34:3700:3b8d:b310:d327:e418] (helo=deadeye) by maynard with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1lGmMj-0002Y3-CX; Mon, 01 Mar 2021 18:29:53 +0100 Received: from ben by deadeye with local (Exim 4.94) (envelope-from ) id 1lGmMi-004iRU-8s; Mon, 01 Mar 2021 18:29:52 +0100 Date: Mon, 1 Mar 2021 18:29:52 +0100 From: Ben Hutchings To: Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, torvalds@linux-foundation.org, stable@vger.kernel.org, Lee Jones , "Luis Claudio R. Goncalves" , lwn@lwn.net, jslaby@suse.cz Subject: Re: futex breakage in 4.9 stable branch Message-ID: References: <161408880177110@kroah.com> <66826ac72356b00814f51487dd1008298e52ed9b.camel@decadent.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="hnV11/jEZcSFOAHY" Content-Disposition: inline In-Reply-To: X-SA-Exim-Connect-IP: 2a02:1811:d34:3700:3b8d:b310:d327:e418 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on maynard); SAEximRunCond expanded to false Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --hnV11/jEZcSFOAHY Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Mar 01, 2021 at 09:07:03AM +0100, Greg Kroah-Hartman wrote: > On Mon, Mar 01, 2021 at 01:13:08AM +0100, Ben Hutchings wrote: > > On Tue, 2021-02-23 at 15:00 +0100, Greg Kroah-Hartman wrote: > > > I'm announcing the release of the 4.9.258 kernel. > > >=20 > > > All users of the 4.9 kernel series must upgrade. > > >=20 > > > The updated 4.9.y git tree can be found at: > > > =A0=A0=A0=A0=A0=A0=A0=A0git://git.kernel.org/pub/scm/linux/kernel/git= /stable/linux-stable.git linux-4.9.y > > > and can be browsed at the normal kernel.org git web browser: > > > =A0=A0=A0=A0=A0=A0=A0=A0 > >=20 > > The backported futex fixes are still incomplete/broken in this version. > > If I enable lockdep and run the futex self-tests (from 5.10): > >=20 > > - on 4.9.246, they pass with no lockdep output > > - on 4.9.257 and 4.9.258, they pass but futex_requeue_pi trigers a > > lockdep splat > >=20 > > I have a local branch that essentially updates futex and rtmutex in > > 4.9-stable to match 4.14-stable. With this, the tests pass and lockdep > > is happy. > >=20 > > Unfortunately, that branch has about another 60 commits. I have now rebased that on top of 4.9.258, and there are "only" 39 commits. > > Further, the > > more we change futex in 4.9, the more difficult it is going to be to > > update the 4.9-rt branch. But I don't see any better option available > > at the moment. > >=20 > > Thoughts? >=20 > There were some posted futex fixes for 4.9 (and 4.4) on the stable list > that I have not gotten to yet. >=20 > Hopefully after these are merged (this week), these issues will be > resolved. I'm afraid they are not sufficient. > If not, then yes, they need to be fixed and any help you can provide > would be appreciated. >=20 > As for "difficulty", yes, it's rough, but the changes backported were > required, for obvious reasons :( I had another look at the locking bug and I was able to make a series of 7 commits (on top of the 2 already queued) that is sufficient to make lockdep happy. But I am not very confident that there won't be other regressions. I'll send that over shortly. Ben. --=20 Ben Hutchings I'm always amazed by the number of people who take up solipsism because they heard someone else explain it. - E*Borg on alt.fan.pratchett --hnV11/jEZcSFOAHY Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEErCspvTSmr92z9o8157/I7JWGEQkFAmA9JIsACgkQ57/I7JWG EQlg1xAA0jQ7fOh7ySmmd/JbnyQw43AcpLzRCIrdvP785nRiiC0bBqaEAdvwW4tK MaukRiiaKB5RIRW6ZVsOu7C0worNwrP62moJejSq2Dper/Lww2Zqi2LqHoaYfdY+ hY5H3gVSSjqOe2eyrC4YJIgkIzv38mcOBqRZIhkPtkJP8qmF5UpRqPd/yhbJOXIE CJhHg0BrtZvjD1XOQrHhjOKXWzWeF9HZlENLFeXdWlofLa/TPpK3XuFNNRuhMy53 hoUR5PvDeSh4m1kKaQE+0n8riynkIujpfHdf9F+gECC6+zABe9c55hS4ukFCxWuN td6uJ+2KRQHuLNB4GKXBeApYnhmRKSrpI1ZeSkTdvEvIzZhQb9B23rkSZCUQVxWT o/vWIDq28E2Q0vl8EUB9exavuO9m4nNexV/dAVQ6t3/z17uziM2kEcw9uFjnEKch 2f6nNyadhYqY+MBSKVMfmWVLyvsuV+GQcIiZcM2QGmYTecVLQ1LN4UI2JntOBTE9 89aHm6djJT1EW3Cs3zdkZZ3CuHsw0QtDeZYBOAkymFeC82i9e1MBRkE1I6KAtf02 B0mQiu7z7f0N1nRftSnnttt2EYpRbR0eDqvnJ/8kK5ejrqCHn2ZJQDnaLYwdBnOT KYoLa+YyG77YMeuj1aiVYurOc4RyQwmCXu8ntS8VcjmBQqBSkbw= =aH3/ -----END PGP SIGNATURE----- --hnV11/jEZcSFOAHY--