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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 0F520C43381 for ; Mon, 11 Mar 2019 13:16:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CCB632084F for ; Mon, 11 Mar 2019 13:16:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727451AbfCKNQC (ORCPT ); Mon, 11 Mar 2019 09:16:02 -0400 Received: from usa-sjc-mx-foss1.foss.arm.com ([217.140.101.70]:54070 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726592AbfCKNQB (ORCPT ); Mon, 11 Mar 2019 09:16:01 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 772CFA78; Mon, 11 Mar 2019 06:16:01 -0700 (PDT) Received: from [10.1.196.69] (e112269-lin.cambridge.arm.com [10.1.196.69]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id EF0293F703; Mon, 11 Mar 2019 06:15:59 -0700 (PDT) From: Steven Price Subject: Re: [PATCH] media: rga: fix NULL pointer dereferences To: Kangjie Lu Cc: Heiko Stuebner , Jacob chen , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, pakki001@umn.edu, Mauro Carvalho Chehab , linux-arm-kernel@lists.infradead.org, linux-media@vger.kernel.org References: <20190309063556.32487-1-kjlu@umn.edu> Message-ID: <6fc9f670-a199-b83d-ff0a-d4cdb8cb80d1@arm.com> Date: Mon, 11 Mar 2019 13:15:58 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.1 MIME-Version: 1.0 In-Reply-To: <20190309063556.32487-1-kjlu@umn.edu> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/03/2019 06:35, Kangjie Lu wrote: > In case __get_free_pages fails, return -ENOMEM to avoid NULL > pointer dereferences. > > Signed-off-by: Kangjie Lu > --- > drivers/media/platform/rockchip/rga/rga.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c > index 5c653287185f..d42b214977a9 100644 > --- a/drivers/media/platform/rockchip/rga/rga.c > +++ b/drivers/media/platform/rockchip/rga/rga.c > @@ -892,8 +892,13 @@ static int rga_probe(struct platform_device *pdev) > > rga->src_mmu_pages = > (unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3); > + if (!rga->src_mmu_pages) > + return -ENOMEM; > + > rga->dst_mmu_pages = > (unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3); > + if (!rga->dst_mmu_pages) > + return -ENOMEM; I believe you need to perform clean up when probe fails, not just return early, e.g. with a 'goto' to the existing clean up code at the end of the function. Also from what I can tell there is already a potential memory leak if video_register_device() fails. You probably want something more like the (completely untested) change below. Steve ----8<---- diff --git a/drivers/media/platform/rockchip/rga/rga.c b/drivers/media/platform/rockchip/rga/rga.c index 5c653287185f..8df1945594ab 100644 --- a/drivers/media/platform/rockchip/rga/rga.c +++ b/drivers/media/platform/rockchip/rga/rga.c @@ -895,6 +895,11 @@ static int rga_probe(struct platform_device *pdev) rga->dst_mmu_pages = (unsigned int *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 3); + if (!rga->src_mmu_pages || !rga->dst_mmu_pages) { + ret = -ENOMEM; + goto free_mem; + } + def_frame.stride = (def_frame.width * def_frame.fmt->depth) >> 3; def_frame.size = def_frame.stride * def_frame.height; @@ -911,6 +916,9 @@ static int rga_probe(struct platform_device *pdev) rel_vdev: video_device_release(vfd); +free_mem: + free_pages((unsigned long)rga->src_mmu_pages, 3); + free_pages((unsigned long)rga->dst_mmu_pages, 3); unreg_video_dev: video_unregister_device(rga->vfd); unreg_v4l2_dev: