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Message-ID: <c03f6f4d-1a7a-4076-af4f-e3d66ace0861@amd.com>
Date: Thu, 30 May 2024 16:25:22 +0530
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 1/1] iommu: Return right value in iommu_sva_bind_device()
To: Lu Baolu <baolu.lu@linux.intel.com>, Joerg Roedel <joro@8bytes.org>,
 Will Deacon <will@kernel.org>, Robin Murphy <robin.murphy@arm.com>,
 Jason Gunthorpe <jgg@ziepe.ca>, Kevin Tian <kevin.tian@intel.com>,
 Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: iommu@lists.linux.dev, linux-kernel@vger.kernel.org
References: <20240528042528.71396-1-baolu.lu@linux.intel.com>
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From: Vasant Hegde <vasant.hegde@amd.com>
In-Reply-To: <20240528042528.71396-1-baolu.lu@linux.intel.com>
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On 5/28/2024 9:55 AM, Lu Baolu wrote:
> iommu_sva_bind_device() should return either a sva bond handle or an
> ERR_PTR value in error cases. Existing drivers (idxd and uacce) only
> check the return value with IS_ERR(). This could potentially lead to
> a kernel NULL pointer dereference issue if the function returns NULL
> instead of an error pointer.
> 
> In reality, this doesn't cause any problems because iommu_sva_bind_device()
> only returns NULL when the kernel is not configured with CONFIG_IOMMU_SVA.
> In this case, iommu_dev_enable_feature(dev, IOMMU_DEV_FEAT_SVA) will
> return an error, and the device drivers won't call iommu_sva_bind_device()
> at all.>
> Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>

-Vasant