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 65C39C4167B for ; Fri, 1 Dec 2023 16:21:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378397AbjLAQVo (ORCPT ); Fri, 1 Dec 2023 11:21:44 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378351AbjLAQVl (ORCPT ); Fri, 1 Dec 2023 11:21:41 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 225D0196 for ; Fri, 1 Dec 2023 08:21:47 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 80714C433C7; Fri, 1 Dec 2023 16:21:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1701447706; bh=OxaoKaXIZz97QSlVLuylRvJDT+kPyPJndjvasxIdAOg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=QDXJugR2UvAVEwMYL/EPAs2rufs3M/7pGlG8EQSqI6FAMEcAIv0Wt6nAJOO6ZugUG nJ4cyQhFMkZpc85ygbt+1eGdiJN0M41Qww1VuD3X+o6mIH6KfxwX2X2Wd2Q3Zni86q /BKZDvlXPEwabj30PiI/oV/WMgpGUsGtH/tsOxL4KtcntPjpYnc45hcmq7uZTSVDUw btH/KJ1xqiFfS+PzLMQRXHbqDtvna/8HrxgDqnzOFozmyLVZn9sgly7F99tJkUhRJ+ wFt9K/FEF97FJL2fk2E/6x2zx5OKULAQcbpdjKp3Ed/Fa2w82MbMQ9nsLiCqdhLnjZ 8WyoXFGg5Mpwg== Date: Fri, 1 Dec 2023 16:21:42 +0000 From: Mark Brown To: Jan =?iso-8859-1?Q?Kundr=E1t?= Cc: Cosmin Tanislav , linux-serial@vger.kernel.org, Andy Shevchenko , linux-kernel@vger.kernel.org Subject: Re: [PATCH] tty: max310x: work around regmap->regcache data corruption Message-ID: References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="S1ok82JjTyGj+vog" Content-Disposition: inline In-Reply-To: X-Cookie: The early worm gets the late bird. Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --S1ok82JjTyGj+vog Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Dec 01, 2023 at 03:51:51PM +0100, Jan Kundr=E1t wrote: > The TL;DR summary is that the regmap_noinc_write spills over the data > that are correctly written to the HW also to the following registers in > the regcache. As a result, regcache then contains user-controlled > garbage which will be used later for bit updates on unrelated registers. > I was investigating a regression that happened somewhere between 5.12.4 > (plus 14 of our patches) and v6.5.9 (plus 7 of our patches). Our Can you reproduce this with current kernels? That's not even an up to date v6.5 - we're up to v6.5.13 now from the looks of things including one upstream fix that looks potentially relevant. The most direct thing would be to write a kunit test demonstrating the issue with current mainline. If things are already fine with mainline then you'd need to talk to the stable maintainers about what they've chosen to backport. =20 --S1ok82JjTyGj+vog Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmVqCBUACgkQJNaLcl1U h9DTMgf/Ymn+p9dkuv6cArGpPGkvboMvHFC62w1huJaKWI3nH93Z9cDd+E123d3o /fM635v3qV5OyCkBS5z78OPA0rZC8hG4Ka5pFPngedNCZ7L7SLi21I9gb3403XQ6 7sCqIyTNVol59GEvalXc5bq6w585qESs2yWZmUKdLQHlUm+JfoGL4EbD85PpMrS9 xcaAUuH5LvnD4i+s4azhDbs5nOaentmWUFXZN5i/AcMOGCZyZESlJ4NOStVzgt6h Q8jMV43gEu4POF1IpCuHUKzi7YJcyn+5+c8kkPXiaSMa2je6SRbymhbdISorfKFh PrU+aJEMDjL2HN8reaaaZaXrAqfcNA== =pihy -----END PGP SIGNATURE----- --S1ok82JjTyGj+vog--