From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: kevin.tian@intel.com, yi.l.liu@intel.com, joro@8bytes.org,
will@kernel.org, robin.murphy@arm.com,
alex.williamson@redhat.com, shuah@kernel.org,
linux-kernel@vger.kernel.org, iommu@lists.linux.dev,
kvm@vger.kernel.org, linux-kselftest@vger.kernel.org,
mjrosato@linux.ibm.com, farman@linux.ibm.com
Subject: Re: [PATCH v11 4/7] iommufd: Use iommufd_access_change_ioas in iommufd_access_destroy_object
Date: Fri, 28 Jul 2023 09:42:45 -0300 [thread overview]
Message-ID: <ZMO3xTrfkeWQ/a6N@nvidia.com> (raw)
In-Reply-To: <f9fbeca2cde7f8515da18d689b3e02a6a40a5e14.1690523699.git.nicolinc@nvidia.com>
On Thu, Jul 27, 2023 at 11:33:26PM -0700, Nicolin Chen wrote:
> Update the unprotect routine in iommufd_access_destroy_object() to calling
> the new iommufd_access_change_ioas() helper. This will reduce some risk of
> race condition with another concurrent iommufd_access_replace/detach call.
>
> Note that the behavior of this function call is changed: a WARN_ON will be
> triggered by a -EBUSY return code if there is another ongoing detach.
This should be completely impossible, at this point the object must
have a refcount of 0 so if another thread is concurrently detaching it
we are already UAFing.
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2023-07-28 12:43 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-28 6:33 [PATCH v11 0/7] Add IO page table replacement support Nicolin Chen
2023-07-28 6:33 ` [PATCH v11 1/7] vfio: Do not allow !ops->dma_unmap in vfio_pin/unpin_pages() Nicolin Chen
2023-07-28 6:33 ` [PATCH v11 2/7] iommufd: Allow passing in iopt_access_list_id to iopt_remove_access() Nicolin Chen
2023-07-28 6:33 ` [PATCH v11 3/7] iommufd: Add iommufd_access_change_ioas(_id) helpers Nicolin Chen
2023-07-28 6:33 ` [PATCH v11 4/7] iommufd: Use iommufd_access_change_ioas in iommufd_access_destroy_object Nicolin Chen
2023-07-28 12:42 ` Jason Gunthorpe [this message]
2023-07-28 6:33 ` [PATCH v11 5/7] iommufd: Add iommufd_access_replace() API Nicolin Chen
2023-07-28 12:43 ` Jason Gunthorpe
2023-07-28 6:33 ` [PATCH v11 6/7] iommufd/selftest: Add IOMMU_TEST_OP_ACCESS_REPLACE_IOAS coverage Nicolin Chen
2023-07-28 6:33 ` [PATCH v11 7/7] vfio: Support IO page table replacement Nicolin Chen
2023-07-28 16:41 ` [PATCH v11 0/7] Add IO page table replacement support Jason Gunthorpe
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