From: Jason Gunthorpe jgg@nvidia.com
commit b4ff830eca097df51af10a9be29e8cc817327919 upstream.
The hwpt is added to the hwpt_list only during its creation, it is never added again. This hunk is some missed leftover from rework. Adding it twice will corrupt the linked list in some cases.
It effects HWPT specific attachment, which is something the test suite cannot cover until we can create a legitimate struct device with a non-system iommu "driver" (ie we need the bus removed from the iommu code)
Cc: stable@vger.kernel.org Fixes: e8d57210035b ("iommufd: Add kAPI toward external drivers for physical devices") Link: https://lore.kernel.org/r/1-v1-4336b5cb2fe4+1d7-iommufd_hwpt_jgg@nvidia.com Reviewed-by: Kevin Tian kevin.tian@intel.com Reported-by: Kevin Tian kevin.tian@intel.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/iommu/iommufd/device.c | 4 ---- 1 file changed, 4 deletions(-)
--- a/drivers/iommu/iommufd/device.c +++ b/drivers/iommu/iommufd/device.c @@ -346,10 +346,6 @@ int iommufd_device_attach(struct iommufd rc = iommufd_device_do_attach(idev, hwpt); if (rc) goto out_put_pt_obj; - - mutex_lock(&hwpt->ioas->mutex); - list_add_tail(&hwpt->hwpt_item, &hwpt->ioas->hwpt_list); - mutex_unlock(&hwpt->ioas->mutex); break; } case IOMMUFD_OBJ_IOAS: {