iommu: Fix error unwind in iommu_group_alloc()

If either iommu_group_grate_file() fails then the
iommu_group is leaked.

Destroy it on these error paths.

Found by kselftest/iommu/iommufd_fail_nth

Fixes: bc7d12b ("iommu: Implement reserved_regions iommu-group sysfs file")
Fixes: c52c72d ("iommu: Add sysfs attribyte for domain type")
Signed-off-by: Jason Gunthorpe <[email protected]>
Reviewed-by: Lu Baolu <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Joerg Roedel <[email protected]>

Author: jgunthorpe

drivers/iommu/iommu.c

@@ -798,12 +798,16 @@ struct iommu_group *iommu_group_alloc(void)
 
 	ret = iommu_group_create_file(group,
 				      &iommu_group_attr_reserved_regions);
-	if (ret)
+	if (ret) {
+		kobject_put(group->devices_kobj);
 		return ERR_PTR(ret);
+	}
 
 	ret = iommu_group_create_file(group, &iommu_group_attr_type);
-	if (ret)
+	if (ret) {
+		kobject_put(group->devices_kobj);
 		return ERR_PTR(ret);
+	}
 
 	pr_debug("Allocated group %d\n", group->id);