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=-15.2 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 BFD29C433DB for ; Wed, 24 Feb 2021 16:42:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6280B64F07 for ; Wed, 24 Feb 2021 16:42:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235483AbhBXQmL (ORCPT ); Wed, 24 Feb 2021 11:42:11 -0500 Received: from foss.arm.com ([217.140.110.172]:39334 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235518AbhBXQkI (ORCPT ); Wed, 24 Feb 2021 11:40:08 -0500 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 1077731B; Wed, 24 Feb 2021 08:39:17 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0028D3F70D; Wed, 24 Feb 2021 08:39:15 -0800 (PST) Subject: Re: [PATCH 1/2] drm/shmem-helper: Check for purged buffers in fault handler To: Neil Roberts , Rob Herring , Tomeu Vizoso , Alyssa Rosenzweig , Robin Murphy Cc: dri-devel@lists.freedesktop.org, stable@vger.kernel.org References: <20210223155125.199577-1-nroberts@igalia.com> <20210223155125.199577-2-nroberts@igalia.com> From: Steven Price Message-ID: <3b720672-d21d-dde5-4d7d-c2c8cd00c4b5@arm.com> Date: Wed, 24 Feb 2021 16:39:32 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210223155125.199577-2-nroberts@igalia.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org On 23/02/2021 15:51, Neil Roberts wrote: > When a buffer is madvised as not needed and then purged, any attempts to > access the buffer from user-space should cause a bus fault. This patch > adds a check for that. > > Cc: stable@vger.kernel.org > Fixes: 17acb9f35ed7 ("drm/shmem: Add madvise state and purge helpers") > Signed-off-by: Neil Roberts Reviewed-by: Steven Price > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 9825c378dfa6..b26139b1dc35 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -525,14 +525,24 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > struct drm_gem_object *obj = vma->vm_private_data; > struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); > loff_t num_pages = obj->size >> PAGE_SHIFT; > + vm_fault_t ret; > struct page *page; > > - if (vmf->pgoff >= num_pages || WARN_ON_ONCE(!shmem->pages)) > - return VM_FAULT_SIGBUS; > + mutex_lock(&shmem->pages_lock); > + > + if (vmf->pgoff >= num_pages || > + WARN_ON_ONCE(!shmem->pages) || > + shmem->madv < 0) { > + ret = VM_FAULT_SIGBUS; > + } else { > + page = shmem->pages[vmf->pgoff]; > > - page = shmem->pages[vmf->pgoff]; > + ret = vmf_insert_page(vma, vmf->address, page); > + } > > - return vmf_insert_page(vma, vmf->address, page); > + mutex_unlock(&shmem->pages_lock); > + > + return ret; > } > > static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) > 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=-15.2 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 E99ADC433E0 for ; Wed, 24 Feb 2021 16:39:20 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 77AD964E24 for ; Wed, 24 Feb 2021 16:39:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 77AD964E24 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=dri-devel-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 52A836EAD8; Wed, 24 Feb 2021 16:39:19 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 248B36EAE3 for ; Wed, 24 Feb 2021 16:39:18 +0000 (UTC) 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 1077731B; Wed, 24 Feb 2021 08:39:17 -0800 (PST) Received: from [192.168.1.179] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 0028D3F70D; Wed, 24 Feb 2021 08:39:15 -0800 (PST) Subject: Re: [PATCH 1/2] drm/shmem-helper: Check for purged buffers in fault handler To: Neil Roberts , Rob Herring , Tomeu Vizoso , Alyssa Rosenzweig , Robin Murphy References: <20210223155125.199577-1-nroberts@igalia.com> <20210223155125.199577-2-nroberts@igalia.com> From: Steven Price Message-ID: <3b720672-d21d-dde5-4d7d-c2c8cd00c4b5@arm.com> Date: Wed, 24 Feb 2021 16:39:32 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210223155125.199577-2-nroberts@igalia.com> Content-Language: en-GB X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: stable@vger.kernel.org, dri-devel@lists.freedesktop.org Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 23/02/2021 15:51, Neil Roberts wrote: > When a buffer is madvised as not needed and then purged, any attempts to > access the buffer from user-space should cause a bus fault. This patch > adds a check for that. > > Cc: stable@vger.kernel.org > Fixes: 17acb9f35ed7 ("drm/shmem: Add madvise state and purge helpers") > Signed-off-by: Neil Roberts Reviewed-by: Steven Price > --- > drivers/gpu/drm/drm_gem_shmem_helper.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c > index 9825c378dfa6..b26139b1dc35 100644 > --- a/drivers/gpu/drm/drm_gem_shmem_helper.c > +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c > @@ -525,14 +525,24 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) > struct drm_gem_object *obj = vma->vm_private_data; > struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj); > loff_t num_pages = obj->size >> PAGE_SHIFT; > + vm_fault_t ret; > struct page *page; > > - if (vmf->pgoff >= num_pages || WARN_ON_ONCE(!shmem->pages)) > - return VM_FAULT_SIGBUS; > + mutex_lock(&shmem->pages_lock); > + > + if (vmf->pgoff >= num_pages || > + WARN_ON_ONCE(!shmem->pages) || > + shmem->madv < 0) { > + ret = VM_FAULT_SIGBUS; > + } else { > + page = shmem->pages[vmf->pgoff]; > > - page = shmem->pages[vmf->pgoff]; > + ret = vmf_insert_page(vma, vmf->address, page); > + } > > - return vmf_insert_page(vma, vmf->address, page); > + mutex_unlock(&shmem->pages_lock); > + > + return ret; > } > > static void drm_gem_shmem_vm_open(struct vm_area_struct *vma) > _______________________________________________ dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel