From: Jason Gunthorpe <jgg@ziepe.ca>
To: Baolu Lu <baolu.lu@linux.intel.com>
Cc: "Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>,
iommu@lists.linux.dev, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, Alexey Kardashevskiy <aik@amd.com>,
Bjorn Helgaas <helgaas@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Joerg Roedel <joro@8bytes.org>,
Jonathan Cameron <jic23@kernel.org>,
Kevin Tian <kevin.tian@intel.com>,
Nicolin Chen <nicolinc@nvidia.com>,
Samuel Ortiz <sameo@rivosinc.com>,
Steven Price <steven.price@arm.com>,
Suzuki K Poulose <Suzuki.Poulose@arm.com>,
Will Deacon <will@kernel.org>,
Xu Yilun <yilun.xu@linux.intel.com>,
Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Subject: Re: [PATCH v4 1/4] iommufd/device: Associate a kvm pointer to iommufd_device
Date: Mon, 27 Apr 2026 11:01:31 -0300 [thread overview]
Message-ID: <20260427140131.GC740385@ziepe.ca> (raw)
In-Reply-To: <f5f2bd86-4cde-4efe-b824-d9f1c82357ac@linux.intel.com>
On Mon, Apr 27, 2026 at 05:07:52PM +0800, Baolu Lu wrote:
> iommufd_device_unbind() is an asynchronous teardown operation. Is it
> possible for idev->kvm to persist or be accessed within the iommufd
> subsystem after iommufd_device_unbind() has returned? Should we add the
> change below to prevent this potential UAF case?
>
> diff --git a/drivers/iommu/iommufd/device.c b/drivers/iommu/iommufd/device.c
> index 170a7005f0bc..dac39cb5e7cc 100644
> --- a/drivers/iommu/iommufd/device.c
> +++ b/drivers/iommu/iommufd/device.c
> @@ -333,6 +333,7 @@ EXPORT_SYMBOL_NS_GPL(iommufd_ctx_has_group, "IOMMUFD");
> */
> void iommufd_device_unbind(struct iommufd_device *idev)
> {
> + idev->kvm = NULL;
> iommufd_object_destroy_user(idev->ictx, &idev->obj);
> }
> EXPORT_SYMBOL_NS_GPL(iommufd_device_unbind, "IOMMUFD");
iommufd_object_destroy_user() frees the memory of idev, it is not
useful to null before free.
Jason
next prev parent reply other threads:[~2026-04-27 14:01 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-27 6:10 [PATCH v4 0/4] Add iommufd ioctls to support TSM operations Aneesh Kumar K.V (Arm)
2026-04-27 6:10 ` [PATCH v4 1/4] iommufd/device: Associate a kvm pointer to iommufd_device Aneesh Kumar K.V (Arm)
2026-04-27 9:07 ` Baolu Lu
2026-04-27 14:01 ` Jason Gunthorpe [this message]
2026-04-27 13:59 ` Jason Gunthorpe
2026-04-27 6:10 ` [PATCH v4 2/4] iommufd/viommu: Associate a kvm pointer to iommufd_viommu Aneesh Kumar K.V (Arm)
2026-04-27 14:03 ` Jason Gunthorpe
2026-04-27 6:10 ` [PATCH v4 3/4] iommufd/tsm: add vdevice TSM bind/unbind ioctl Aneesh Kumar K.V (Arm)
2026-04-27 6:10 ` [PATCH v4 4/4] iommufd/vdevice: add TSM guest request ioctl Aneesh Kumar K.V (Arm)
2026-04-27 14:05 ` Jason Gunthorpe
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