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,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_2 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 1084EC433DB for ; Tue, 26 Jan 2021 13:52:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C998B2255F for ; Tue, 26 Jan 2021 13:52:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405557AbhAZNv4 convert rfc822-to-8bit (ORCPT ); Tue, 26 Jan 2021 08:51:56 -0500 Received: from foss.arm.com ([217.140.110.172]:40910 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405443AbhAZNvk (ORCPT ); Tue, 26 Jan 2021 08:51:40 -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 E477B31B; Tue, 26 Jan 2021 05:50:54 -0800 (PST) Received: from localhost (unknown [10.57.43.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id A47043F68F; Tue, 26 Jan 2021 05:50:53 -0800 (PST) Date: Tue, 26 Jan 2021 13:50:40 +0000 From: Robin Murphy To: Shameer Kolothum Cc: , , jean-philippe@linaro.org, will@kernel.org, linuxarm@openeuler.org, prime.zeng@hisilicon.com Subject: Re: [PATCH] iommu: Check dev->iommu in iommu_dev_xxx functions Message-ID: <20210126135039.000039a0@arm.com> In-Reply-To: <20210126130629.8928-1-shameerali.kolothum.thodi@huawei.com> References: <20210126130629.8928-1-shameerali.kolothum.thodi@huawei.com> X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 26 Jan 2021 13:06:29 +0000 Shameer Kolothum wrote: > The device iommu probe/attach might have failed leaving dev->iommu > to NULL and device drivers may still invoke these functions resulting > a crash in iommu vendor driver code. Hence make sure we check that. > > Signed-off-by: Shameer Kolothum > --- > drivers/iommu/iommu.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index ffeebda8d6de..cb68153c5cc0 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2867,7 +2867,7 @@ bool iommu_dev_has_feature(struct device *dev, > enum iommu_dev_features feat) { > const struct iommu_ops *ops = dev->bus->iommu_ops; > > - if (ops && ops->dev_has_feat) > + if (dev->iommu && ops && ops->dev_has_feat) > return ops->dev_has_feat(dev, feat); Might make sense to make these more self-contained, e.g.: if (dev->iommu && dev->iommu->ops->foo) dev->iommu->ops->foo() Robin. > return false; > @@ -2878,7 +2878,7 @@ int iommu_dev_enable_feature(struct device > *dev, enum iommu_dev_features feat) { > const struct iommu_ops *ops = dev->bus->iommu_ops; > > - if (ops && ops->dev_enable_feat) > + if (dev->iommu && ops && ops->dev_enable_feat) > return ops->dev_enable_feat(dev, feat); > > return -ENODEV; > @@ -2894,7 +2894,7 @@ int iommu_dev_disable_feature(struct device > *dev, enum iommu_dev_features feat) { > const struct iommu_ops *ops = dev->bus->iommu_ops; > > - if (ops && ops->dev_disable_feat) > + if (dev->iommu && ops && ops->dev_disable_feat) > return ops->dev_disable_feat(dev, feat); > > return -EBUSY; > @@ -2905,7 +2905,7 @@ bool iommu_dev_feature_enabled(struct device > *dev, enum iommu_dev_features feat) { > const struct iommu_ops *ops = dev->bus->iommu_ops; > > - if (ops && ops->dev_feat_enabled) > + if (dev->iommu && ops && ops->dev_feat_enabled) > return ops->dev_feat_enabled(dev, feat); > > return false;