From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753006AbdHXMxe (ORCPT ); Thu, 24 Aug 2017 08:53:34 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:31651 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751554AbdHXMxd (ORCPT ); Thu, 24 Aug 2017 08:53:33 -0400 Date: Thu, 24 Aug 2017 15:53:12 +0300 From: Dan Carpenter To: Baoquan He Cc: iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, joro@8bytes.org Subject: Re: [PATCH] iommu/amd: Check if domain is NULL before dereference it Message-ID: <20170824125311.ymx27viis6rnhozy@mwanda> References: <1503575807-15746-1-git-send-email-bhe@redhat.com> <20170824121137.dgsy57bq3qsjvjqj@mwanda> <20170824122251.GG19768@x1> <20170824123226.57twp5sdh246l5kz@mwanda> <20170824124733.GH19768@x1> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170824124733.GH19768@x1> User-Agent: NeoMutt/20170113 (1.7.2) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 24, 2017 at 08:47:33PM +0800, Baoquan He wrote: > On 08/24/17 at 03:32pm, Dan Carpenter wrote: > > Take a look at this code for example. But all the places which call > > get_domain() are the same: > > > > drivers/iommu/amd_iommu.c > > 2648 page = virt_to_page(virt_addr); > > 2649 size = PAGE_ALIGN(size); > > 2650 > > 2651 domain = get_domain(dev); > > ^^^^^^^^^^^^^^ > > imagined get_domain() returns NULL. > > > > 2652 if (IS_ERR(domain)) > > 2653 goto free_mem; > > 2654 > > 2655 dma_dom = to_dma_ops_domain(domain); > > ^^^^^^^^^^^^^^^^^^^^^^^^^ > > This will Oops. > > I see, it's a problem. Thanks for telling! > > How about below change? But I am not very sure which errno should be > picked, seems the latter one, EBUSY is better since it has passed the > check_device() checking. Looks good to me. You know better than I do which errno is best, so I'll leave that to you. regards, dan carpenter