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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 3F806C31E4A for ; Thu, 13 Jun 2019 15:47:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23354208CA for ; Thu, 13 Jun 2019 15:47:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731928AbfFMPrY (ORCPT ); Thu, 13 Jun 2019 11:47:24 -0400 Received: from foss.arm.com ([217.140.110.172]:37030 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731766AbfFMJa4 (ORCPT ); Thu, 13 Jun 2019 05:30:56 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CC43C367; Thu, 13 Jun 2019 02:30:55 -0700 (PDT) Received: from [10.1.197.57] (e110467-lin.cambridge.arm.com [10.1.197.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3FF5A3F694; Thu, 13 Jun 2019 02:30:55 -0700 (PDT) Subject: Re: [bug report] ACPI: Add new IORT functions to support MSI domain handling To: Dan Carpenter , tn@semihalf.com Cc: linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org References: <20190613065410.GB16334@mwanda> From: Robin Murphy Message-ID: <425b5d78-b38f-270b-94e2-7ece1e5498e5@arm.com> Date: Thu, 13 Jun 2019 10:30:35 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <20190613065410.GB16334@mwanda> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org On 13/06/2019 07:54, Dan Carpenter wrote: > Hello Tomasz Nowicki, > > The patch 4bf2efd26d76: "ACPI: Add new IORT functions to support MSI > domain handling" from Sep 12, 2016, leads to the following static > checker warning: > > drivers/acpi/arm64/iort.c:628 iort_dev_find_its_id() > warn: array off by one? 'its->identifiers[idx]' > > drivers/acpi/arm64/iort.c > 589 /** > 590 * iort_dev_find_its_id() - Find the ITS identifier for a device > 591 * @dev: The device. > 592 * @req_id: Device's requester ID > 593 * @idx: Index of the ITS identifier list. > 594 * @its_id: ITS identifier. > 595 * > 596 * Returns: 0 on success, appropriate error value otherwise > 597 */ > 598 static int iort_dev_find_its_id(struct device *dev, u32 req_id, > 599 unsigned int idx, int *its_id) > 600 { > 601 struct acpi_iort_its_group *its; > 602 struct acpi_iort_node *node; > 603 > 604 node = iort_find_dev_node(dev); > 605 if (!node) > 606 return -ENXIO; > 607 > 608 node = iort_node_map_id(node, req_id, NULL, IORT_MSI_TYPE); > 609 if (!node) > 610 return -ENXIO; > 611 > 612 /* Move to ITS specific data */ > 613 its = (struct acpi_iort_its_group *)node->node_data; > 614 if (idx > its->its_count) { > ^^^^^^^^^^^^^^^^^^^^ > I wasn't able to find any information about how its->its_count is set > but it looks to me that is off by one. its->count is read directly from the firmware table. Currently it seems this condition can never be hit anyway, since this is only ever called with idx == 0. TBH I can't really see how the code could evolve such that this check should ever be necessary (i.e. it makes no sense for callers to pull idx values out if thin air, so they'd presumably end up being derived from its->count in the first place), but if we are going to have it then I agree it should be ">=". Robin. > > 615 dev_err(dev, "requested ITS ID index [%d] is greater than available [%d]\n", > 616 idx, its->its_count); > 617 return -ENXIO; > 618 } > 619 > 620 *its_id = its->identifiers[idx]; > 621 return 0; > 622 } > > regards, > dan carpenter > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >