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=-6.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 ACBD8C433DF for ; Fri, 31 Jul 2020 13:55:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8296E22B40 for ; Fri, 31 Jul 2020 13:55:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=sang-engineering.com header.i=@sang-engineering.com header.b="GpljosT9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730706AbgGaNzc (ORCPT ); Fri, 31 Jul 2020 09:55:32 -0400 Received: from www.zeus03.de ([194.117.254.33]:36594 "EHLO mail.zeus03.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732402AbgGaNzc (ORCPT ); Fri, 31 Jul 2020 09:55:32 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=simple; d=sang-engineering.com; h= date:from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to; s=k1; bh=UowO9dFG8ngxMdaq5/AOFmxXrA6A eQawaeMQ0zmHxF4=; b=GpljosT9Ypquy0Qcromr280Wvy+KC6z4es7GuG9iafoL Xc6doXewqAWTmug2z9rrxmnDNws9PHfCti42W7t5QllKDVUrIk3C8AcK5eEWAJAn dh8xILiR4Y5rJ4vb3l7TEPYkRuA/4iehDk7asn5YHoINRCJhOisd9L42WIkG4QQ= Received: (qmail 1608537 invoked from network); 31 Jul 2020 15:55:30 +0200 Received: by mail.zeus03.de with ESMTPSA (TLS_AES_256_GCM_SHA384 encrypted, authenticated); 31 Jul 2020 15:55:30 +0200 X-UD-Smtp-Session: l3s3148p1@nAJWJL2rhOhQT+F6 Date: Fri, 31 Jul 2020 15:55:30 +0200 From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-renesas-soc@vger.kernel.org, Ray Jui , Scott Branden , Dhananjay Phadke , bcm-kernel-feedback-list@broadcom.com, Rayagonda Kokatanur Subject: Re: [PATCH] i2c: rcar: avoid race when unregistering slave Message-ID: <20200731135530.GC1679@kunai> References: <20200726161606.15315-1-wsa+renesas@sang-engineering.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="CblX+4bnyfN0pR09" Content-Disposition: inline In-Reply-To: <20200726161606.15315-1-wsa+renesas@sang-engineering.com> Sender: linux-i2c-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org --CblX+4bnyfN0pR09 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Jul 26, 2020 at 06:16:06PM +0200, Wolfram Sang wrote: > Due to the lockless design of the driver, it is theoretically possible > to access a NULL pointer, if a slave interrupt was running while we were > unregistering the slave. To make this rock solid, disable the interrupt > for a short time while we are clearing the interrupt_enable register. > This patch is purely based on code inspection. The OOPS is super-hard to > trigger because clearing SAR (the address) makes interrupts even more > unlikely to happen as well. While here, reinit SCR to SDBS because this > bit should always be set according to documentation. There is no effect, > though, because the interface is disabled. >=20 > Signed-off-by: Wolfram Sang Applied to for-next, thanks! --CblX+4bnyfN0pR09 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEOZGx6rniZ1Gk92RdFA3kzBSgKbYFAl8kItEACgkQFA3kzBSg Kba2aQ//fRf6nU1nrdjBSoh1xn8AYxG2COLDQLMxFYmJdV/TBziC0+QG4rieUhk9 KAdTu02ZAuKFPAzFryWEwoGKu1cDgXsM7OJdnlK3TVDu3LRKnEo4rctkspKnVuBp VXL6nYyKCC4Uon0Vsq4RsonFk3V6Xp6X00xhVWOMAGbL9OizftDE3bbjnGtiL5ls oqYqT9IkYalZUh6O6uLqZVAavcZ06yA0anemKEqkmvwf9w0+F5uiMt5TEktnceZf H0Q4JCEwVW5iFT6o1yhRwo4H/1BqZAaXtqntj0/MXX2Gtzorpnsy28aWGYvLZIy7 8PEPPXCZN/s44q4DSdPBOokAPwtQ0Kdc2a4DUj5W0TRtLwRmB0B7SbG22MDAsNz/ dJ2ya4hPjZ+bh833+E6nVseR559cQ6yHheb5gvvjjxGLzCXBO2Ul3UnQqRVzmOOo hLN7/FRmimS2gNi40a/DS0NdvhJuNS3hEjaHjzG80hRdfPn1v+bzF1X0in68bbtT rrEfB4qh6IXXX9kqwgpU3B8JCKOPHLFZDyLSbIcYekh962Mx79rnlLHiCiisD5/y CmCsHORRpseaX36vXcDLV9rMPXDyhqm8gywhrF61zasrzWKxhz6mRhfGPYuaziYw AvsElvVTPGYzokf8op93geU1uKw4FHk12aONc90UTKAFBRwEnRQ= =iKy9 -----END PGP SIGNATURE----- --CblX+4bnyfN0pR09--