On Fri, Oct 25, 2024 at 04:49:49PM -0700, Nicolin Chen wrote: > For an iommu_dev that can unplug (so far only this selftest does so), the > viommu->iommu_dev pointer has no guarantee of its life cycle after it is > copied from the idev->dev->iommu->iommu_dev. > > Track the user count of the iommu_dev. Postpone the exit routine using a > completion, if refcount is unbalanced. The refcount inc/dec will be added > in the following patch. > > Signed-off-by: Nicolin Chen <nicolinc@xxxxxxxxxx> > --- > drivers/iommu/iommufd/selftest.c | 32 ++++++++++++++++++++++++-------- > 1 file changed, 24 insertions(+), 8 deletions(-) Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx> Since this is built into the iommufd module it can't be unloaded without also unloading iommufd, which is impossible as long as any iommufd FDs are open. So I expect that the WARN_ON can never happen. Jason
