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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 AD412C76188 for ; Mon, 22 Jul 2019 11:43:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 86FA32184E for ; Mon, 22 Jul 2019 11:43:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728825AbfGVLnG (ORCPT ); Mon, 22 Jul 2019 07:43:06 -0400 Received: from verein.lst.de ([213.95.11.211]:59758 "EHLO verein.lst.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726339AbfGVLnF (ORCPT ); Mon, 22 Jul 2019 07:43:05 -0400 Received: by verein.lst.de (Postfix, from userid 2407) id E6A1868B20; Mon, 22 Jul 2019 13:43:03 +0200 (CEST) Date: Mon, 22 Jul 2019 13:43:03 +0200 From: Christoph Hellwig To: Eric Auger Cc: eric.auger.pro@gmail.com, hch@lst.de, m.szyprowski@samsung.com, robin.murphy@arm.com, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] dma-mapping: Protect dma_addressing_limited against NULL dma_mask Message-ID: <20190722114303.GA32052@lst.de> References: <20190722111449.29258-1-eric.auger@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190722111449.29258-1-eric.auger@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I posted a fix that takes care of this in SCSI this morning: https://marc.info/?l=linux-scsi&m=156378725427719&w=2 I suspect for virtio-blk we should do the same. > static inline bool dma_addressing_limited(struct device *dev) > { > - return min_not_zero(*dev->dma_mask, dev->bus_dma_mask) < > - dma_get_required_mask(dev); > + return dev->dma_mask ? min_not_zero(*dev->dma_mask, dev->bus_dma_mask) < > + dma_get_required_mask(dev) : false; But to be on the safe side we could still do an early return here, but it should have a WARN_ON_ONCE.