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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 0A5A6C433ED for ; Mon, 10 May 2021 21:36:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C0FC860FE7 for ; Mon, 10 May 2021 21:36:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232288AbhEJVhp (ORCPT ); Mon, 10 May 2021 17:37:45 -0400 Received: from gate.crashing.org ([63.228.1.57]:57318 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230165AbhEJVhn (ORCPT ); Mon, 10 May 2021 17:37:43 -0400 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 14ALElMY017988; Mon, 10 May 2021 16:14:47 -0500 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 14ALEiiv017985; Mon, 10 May 2021 16:14:44 -0500 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Mon, 10 May 2021 16:14:44 -0500 From: Segher Boessenkool To: Christophe Leroy Cc: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , pmenzel@molgen.mpg.de, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] powerpc/legacy_serial: Fix UBSAN: array-index-out-of-bounds Message-ID: <20210510211444.GE10366@gate.crashing.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, May 08, 2021 at 06:36:21AM +0000, Christophe Leroy wrote: > UBSAN complains when a pointer is calculated with invalid > 'legacy_serial_console' index, allthough the index is verified > before dereferencing the pointer. Addressing like this is UB already. You could just move this: > - if (legacy_serial_console < 0) > - return 0; to before > - struct legacy_serial_info *info = &legacy_serial_infos[legacy_serial_console]; > - struct plat_serial8250_port *port = &legacy_serial_ports[legacy_serial_console]; and no other change is necessary. Segher