Messages in this thread | | | Date | Fri, 28 Jul 2023 09:42:45 -0300 | From | Jason Gunthorpe <> | Subject | Re: [PATCH v11 4/7] iommufd: Use iommufd_access_change_ioas in iommufd_access_destroy_object |
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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
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