--- x/drivers/iommu/iommufd/hw_pagetable.c
+++ y/drivers/iommu/iommufd/hw_pagetable.c
@@ -110,8 +110,11 @@ iommufd_hw_pagetable_alloc(struct iommuf
 	return hwpt;
 
 out_detach:
-	if (immediate_attach)
+	if (immediate_attach) {
+		mutex_lock(&idev->igroup->lock);
 		iommufd_hw_pagetable_detach(idev);
+		mutex_unlock(&idev->igroup->lock);
+	}
 out_abort:
 	iommufd_object_abort_and_destroy(ictx, &hwpt->obj);
 	return ERR_PTR(rc);