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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 039F7C433E0 for ; Wed, 8 Jul 2020 06:53:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C71CF20760 for ; Wed, 8 Jul 2020 06:53:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594191216; bh=g9ZlohxdxkjqpTSIdab6cJipB+jvPoyU/B+zybZjQug=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=rSDxv+l08+SWK56HW/bvcQ1p8Zi2isQZWCF+fvTZXklHxmIPtLeq6gmQYkB+CXAzE dvt3ijHgCysPK51/A4Akmy1sDXrQFFG9isdHVgV1mMQop82U0RYeNFq1ZPbPmgUsL4 iUOdTYWteFAWj9bxYbz5C5pM3g/kaV9kbJXbIitk= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729748AbgGHGxf (ORCPT ); Wed, 8 Jul 2020 02:53:35 -0400 Received: from mail.kernel.org ([198.145.29.99]:58106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729535AbgGHGxf (ORCPT ); Wed, 8 Jul 2020 02:53:35 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 588792075B; Wed, 8 Jul 2020 06:53:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1594191214; bh=g9ZlohxdxkjqpTSIdab6cJipB+jvPoyU/B+zybZjQug=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=JZMg1ldP1BXdzQiHMFkXu7aHxwTh64Vlhyckb9kaTg+GWWZzMNEut8mTQb8xJ+Y4D N6v87HtjIX4uGta6CD2crc/ju2GwnO835wcPKSVZaV67/yxL6pytZe0r1v5nIf5b3+ GDOWbSJYBqXmNDU02c6mR1J92fhfjTPWRzjOnU9Q= Date: Wed, 8 Jul 2020 08:53:30 +0200 From: Greg Kroah-Hartman To: Saheed Olayemi Bolarinwa Cc: helgaas@kernel.org, Arnd Bergmann , bjorn@helgaas.com, skhan@linuxfoundation.org, linux-kernel-mentees@lists.linuxfoundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/13] misc: rtsx: Check the return value of pcie_capability_read_*() Message-ID: <20200708065330.GA348669@kroah.com> References: <20200707220324.8425-1-refactormyself@gmail.com> <20200707220324.8425-3-refactormyself@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200707220324.8425-3-refactormyself@gmail.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 08, 2020 at 12:03:13AM +0200, Saheed Olayemi Bolarinwa wrote: > From: Bolarinwa Olayemi Saheed > > On failure pcie_capability_read_dword() sets it's last parameter, val > to 0. In which case (val & PCI_EXP_DEVCTL2_LTR_EN) evaluates to 0. > However, with Patch 13/13, it is possible that val is set to ~0 on > failure. This would introduce a bug because (x & x) == (~0 & x). > > This bug can be avoided without changing the function's behaviour if the > return value of pcie_capability_read_word is checked to confirm success. > > Check the return value of pcie_capability_read_word() to ensure success. > > Suggested-by: Bjorn Helgaas > Signed-off-by: Bolarinwa Olayemi Saheed Acked-by: Greg Kroah-Hartman