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From: "Tian, Kevin" <kevin.tian@intel.com>
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>, Jean-Philippe Brucker <jean-philippe@linaro.org>
CC: "iommu@lists.linux.dev" <iommu@lists.linux.dev>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 1/1] iommu: Return right value in iommu_sva_bind_device()
Thread-Topic: [PATCH 1/1] iommu: Return right value in iommu_sva_bind_device()
Thread-Index: AQHasLduihaQeYMyCUyP+1BFuevGQ7Gtfi/g
Date: Wed, 29 May 2024 02:28:10 +0000
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References: <20240528042528.71396-1-baolu.lu@linux.intel.com>
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> From: Lu Baolu <baolu.lu@linux.intel.com>
> Sent: Tuesday, May 28, 2024 12:25 PM
>=20
> 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.
>=20
> 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.
>=20
> Fixes: 26b25a2b98e4 ("iommu: Bind process address spaces to devices")
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>

Reviewed-by: Kevin Tian <kevin.tian@intel.com>