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iommufd: Use iommufd_access_change_ioas in iommufd_access_destroy_object

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Update iommufd_access_destroy_object() to call the new
iommufd_access_change_ioas() helper.

It is impossible to legitimately race iommufd_access_destroy_object() with
iommufd_access_change_ioas() as iommufd_access_destroy_object() is only
called once the refcount reache zero, so any concurrent
iommufd_access_change_ioas() is already UAFing the memory.

Link: https://lore.kernel.org/r/f9fbeca2cde7f8515da18d689b3e02a6a40a5e14.1690523699.git.nicolinc@nvidia.com
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
This commit is contained in:
Nicolin Chen 2023-07-27 23:33:26 -07:00 committed by Jason Gunthorpe
parent 9227da7816
commit 6129b59fcd
1 changed files with 4 additions and 6 deletions
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10
drivers/iommu/iommufd/device.c
View file

@ -753,12 +753,10 @@ void iommufd_access_destroy_object(struct iommufd_object *obj)
struct iommufd_access *access =
container_of(obj, struct iommufd_access, obj);
if (access->ioas) {
iopt_remove_access(&access->ioas->iopt, access,
access->iopt_access_list_id);
refcount_dec(&access->ioas->obj.users);
access->ioas = NULL;
}
mutex_lock(&access->ioas_lock);
if (access->ioas)
WARN_ON(iommufd_access_change_ioas(access, NULL));
mutex_unlock(&access->ioas_lock);
iommufd_ctx_put(access->ictx);
}