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=-15.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham 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 3B2D2C4338F for ; Thu, 29 Jul 2021 16:13:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 245EC604DB for ; Thu, 29 Jul 2021 16:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229542AbhG2QNl (ORCPT ); Thu, 29 Jul 2021 12:13:41 -0400 Received: from mga04.intel.com ([192.55.52.120]:42247 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229485AbhG2QNl (ORCPT ); Thu, 29 Jul 2021 12:13:41 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10060"; a="211035522" X-IronPort-AV: E=Sophos;i="5.84,278,1620716400"; d="scan'208";a="211035522" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2021 09:12:04 -0700 X-IronPort-AV: E=Sophos;i="5.84,278,1620716400"; d="scan'208";a="465130370" Received: from djiang5-mobl1.amr.corp.intel.com (HELO [10.209.170.107]) ([10.209.170.107]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2021 09:12:04 -0700 Subject: Re: [PATCH] dmaengine: idxd: Fix a possible NULL pointer dereference To: Christophe JAILLET , vkoul@kernel.org, dan.j.williams@intel.com Cc: dmaengine@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org References: <77f0dc4f3966591d1f0cffb614a94085f8895a85.1627560174.git.christophe.jaillet@wanadoo.fr> From: Dave Jiang Message-ID: <44c9607e-2cde-02b9-7e4e-68578a775fb3@intel.com> Date: Thu, 29 Jul 2021 09:12:03 -0700 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: <77f0dc4f3966591d1f0cffb614a94085f8895a85.1627560174.git.christophe.jaillet@wanadoo.fr> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org On 7/29/2021 5:04 AM, Christophe JAILLET wrote: > 'device_driver_attach()' dereferences its first argument (i.e. 'alt_drv') > so it must not be NULL. > Simplify the error handling logic about NULL 'alt_drv' in order to be > more robust and future-proof. > > Fixes: 568b2126466f ("dmaengine: idxd: fix uninit var for alt_drv") > Fixes: 6e7f3ee97bbe ("dmaengine: idxd: move dsa_drv support to compatible mode") > > Signed-off-by: Christophe JAILLET Thanks for the cleanup. Acked-by: Dave Jiang > --- > drivers/dma/idxd/compat.c | 15 ++++----------- > 1 file changed, 4 insertions(+), 11 deletions(-) > > diff --git a/drivers/dma/idxd/compat.c b/drivers/dma/idxd/compat.c > index d7616c240dcd..3df21615f888 100644 > --- a/drivers/dma/idxd/compat.c > +++ b/drivers/dma/idxd/compat.c > @@ -45,23 +45,16 @@ static ssize_t bind_store(struct device_driver *drv, const char *buf, size_t cou > idxd_dev = confdev_to_idxd_dev(dev); > if (is_idxd_dev(idxd_dev)) { > alt_drv = driver_find("idxd", bus); > - if (!alt_drv) > - return -ENODEV; > } else if (is_idxd_wq_dev(idxd_dev)) { > struct idxd_wq *wq = confdev_to_wq(dev); > > - if (is_idxd_wq_kernel(wq)) { > + if (is_idxd_wq_kernel(wq)) > alt_drv = driver_find("dmaengine", bus); > - if (!alt_drv) > - return -ENODEV; > - } else if (is_idxd_wq_user(wq)) { > + else if (is_idxd_wq_user(wq)) > alt_drv = driver_find("user", bus); > - if (!alt_drv) > - return -ENODEV; > - } else { > - return -ENODEV; > - } > } > + if (!alt_drv) > + return -ENODEV; > > rc = device_driver_attach(alt_drv, dev); > if (rc < 0)