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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,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 C6564C76188 for ; Mon, 22 Jul 2019 14:55:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A5FA42190F for ; Mon, 22 Jul 2019 14:55:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726653AbfGVOz2 (ORCPT ); Mon, 22 Jul 2019 10:55:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:48972 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725899AbfGVOzY (ORCPT ); Mon, 22 Jul 2019 10:55:24 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 64F94308A968; Mon, 22 Jul 2019 14:55:24 +0000 (UTC) Received: from laptop.redhat.com (ovpn-116-45.ams2.redhat.com [10.36.116.45]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1002A60A9F; Mon, 22 Jul 2019 14:55:21 +0000 (UTC) From: Eric Auger To: eric.auger.pro@gmail.com, eric.auger@redhat.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/2] virtio/virtio_ring: Fix the dma_max_mapping_size call Date: Mon, 22 Jul 2019 16:55:09 +0200 Message-Id: <20190722145509.1284-3-eric.auger@redhat.com> In-Reply-To: <20190722145509.1284-1-eric.auger@redhat.com> References: <20190722145509.1284-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.41]); Mon, 22 Jul 2019 14:55:24 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Do not call dma_max_mapping_size for devices that have no DMA mask set, otherwise we can hit a NULL pointer dereference. This occurs when a virtio-blk-pci device is protected with a virtual IOMMU. Fixes: e6d6dd6c875e ("virtio: Introduce virtio_max_dma_size()") Signed-off-by: Eric Auger Suggested-by: Christoph Hellwig --- drivers/virtio/virtio_ring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c8be1c4f5b55..37c143971211 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -262,7 +262,7 @@ size_t virtio_max_dma_size(struct virtio_device *vdev) { size_t max_segment_size = SIZE_MAX; - if (vring_use_dma_api(vdev)) + if (vring_use_dma_api(vdev) && vdev->dev.dma_mask) max_segment_size = dma_max_mapping_size(&vdev->dev); return max_segment_size; -- 2.20.1