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=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 AAE18C7618F for ; Mon, 22 Jul 2019 16:56:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 82A7C21738 for ; Mon, 22 Jul 2019 16:56:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729542AbfGVQ44 (ORCPT ); Mon, 22 Jul 2019 12:56:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:54194 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728343AbfGVQ44 (ORCPT ); Mon, 22 Jul 2019 12:56:56 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id C400C3082133; Mon, 22 Jul 2019 16:56:55 +0000 (UTC) Received: from [10.36.116.45] (ovpn-116-45.ams2.redhat.com [10.36.116.45]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4B74719D71; Mon, 22 Jul 2019 16:56:51 +0000 (UTC) Subject: Re: [PATCH v2] dma-mapping: Use dma_get_mask in dma_addressing_limited To: eric.auger.pro@gmail.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 References: <20190722165149.3763-1-eric.auger@redhat.com> From: Auger Eric Message-ID: <77ba1061-08b6-421e-a6dd-d5db9851325b@redhat.com> Date: Mon, 22 Jul 2019 18:56:49 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <20190722165149.3763-1-eric.auger@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.42]); Mon, 22 Jul 2019 16:56:55 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Christoph, On 7/22/19 6:51 PM, Eric Auger wrote: > We currently have cases where the dma_addressing_limited() gets > called with dma_mask unset. This causes a NULL pointer dereference. > > Use dma_get_mask() accessor to prevent the crash. > > Fixes: b866455423e0 ("dma-mapping: add a dma_addressing_limited helper") > Signed-off-by: Eric Auger As a follow-up of my last email, here is a patch featuring dma_get_mask(). But you don't have the WARN_ON_ONCE anymore, pointing out suspect users. Feel free to pick up your preferred approach Thanks Eric > > --- > > v1 -> v2: > - was [PATCH 1/2] dma-mapping: Protect dma_addressing_limited > against NULL dma_mask > - Use dma_get_mask > --- > include/linux/dma-mapping.h | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h > index e11b115dd0e4..f7d1eea32c78 100644 > --- a/include/linux/dma-mapping.h > +++ b/include/linux/dma-mapping.h > @@ -689,8 +689,8 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask) > */ > 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 min_not_zero(dma_get_mask(dev), dev->bus_dma_mask) < > + dma_get_required_mask(dev); > } > > #ifdef CONFIG_ARCH_HAS_SETUP_DMA_OPS >