From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0CC8F370 for ; Fri, 14 Oct 2022 01:52:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1665712370; x=1697248370; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=Tvf1KEUmmFWCZG5Vqpb9xVTMOaAK+dTPvxZXl2xkreQ=; b=cOlsBXb5a0pk52uwBV+TeKgUo6B3rb8qqCQVGup+8SSVP4mKD7FTPiV2 sXjWTiNjJBz298ID5Pvm2hoILWl2PNxRmgZS5rSjoFwI10OfHszuVREa4 gHZHpK2VG7WJN/PaMnf+H/scCEbKY2dPgoD4jn/y5xqHObCNKpZAMqKqj SjPhVEHJU3gS2jqjeEznbKqIJyCZFPYM0vQa0qNrXrM86XPa/B9iZW2UL NNPgjil6rNhlRd3E5XHM7lEpGKmL9WTdXxWEOq2/iubccD+v0bD6izwXh Wgx5ANv0yO+ZdzBqG5lkwj0nAdaHxEaryd5jLk4QCPQHGlDGxSzDydiAe A==; X-IronPort-AV: E=McAfee;i="6500,9779,10499"; a="302868484" X-IronPort-AV: E=Sophos;i="5.95,182,1661842800"; d="scan'208";a="302868484" Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2022 18:52:49 -0700 X-IronPort-AV: E=McAfee;i="6500,9779,10499"; a="627401441" X-IronPort-AV: E=Sophos;i="5.95,182,1661842800"; d="scan'208";a="627401441" Received: from blu2-mobl3.ccr.corp.intel.com (HELO [10.254.210.33]) ([10.254.210.33]) by orsmga002-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Oct 2022 18:52:46 -0700 Message-ID: <89029bfb-bdf6-43e3-b24c-09c266277f0e@linux.intel.com> Date: Fri, 14 Oct 2022 09:52:44 +0800 Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.3.2 Cc: baolu.lu@linux.intel.com, Joerg Roedel , Will Deacon , Robin Murphy Subject: Re: [RFC PATCH] iommu/vt-d: Add sanity check to iommu_sva_bind_device() Content-Language: en-US To: Jerry Snitselaar , iommu@lists.linux.dev, linux-kernel@vger.kernel.org References: <20221013153355.2365865-1-jsnitsel@redhat.com> From: Baolu Lu In-Reply-To: <20221013153355.2365865-1-jsnitsel@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2022/10/13 23:33, Jerry Snitselaar wrote: > iommu_sva_bind_device() should only be called if > iommu_dev_enable_feature() succeeded. There has been one case already > where that hasn't been the case, which resulted in a null pointer > deref in dev_iommu_ops(). To avoid that happening in the future if > another driver makes that mistake, sanity check dev->iommu and > dev->iommu->iommu_dev prior to calling dev_iommu_ops(). > > Cc: Joerg Roedel > Cc: Will Deacon > Cc: Robin Murphy > Cc: Lu Baolu > Signed-off-by: Jerry Snitselaar > --- > drivers/iommu/iommu.c | 10 +++++++++- > 1 file changed, 9 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index 4893c2429ca5..20ec75667529 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -2746,7 +2746,15 @@ iommu_sva_bind_device(struct device *dev, struct mm_struct *mm, void *drvdata) > { > struct iommu_group *group; > struct iommu_sva *handle = ERR_PTR(-EINVAL); > - const struct iommu_ops *ops = dev_iommu_ops(dev); > + const struct iommu_ops *ops; > + > + if (!dev->iommu || !dev->iommu->iommu_dev) { > + dev_warn(dev, "%s called without checking succes of iommu_dev_enable_feature?\n", > + __func__); > + return ERR_PTR(-ENODEV); > + } If that's the case, dev_iommu_ops() will warn a NULL pointer reference. This kind of error will be discovered at the first place. Best regards, baolu > + > + ops = dev_iommu_ops(dev); > > if (!ops->sva_bind) > return ERR_PTR(-ENODEV);