27 Oct
2021
27 Oct
'21
11:42 a.m.
The livepatch code uses workqueue because the livepatch can be disabled via sysfs interface. It obviously could not wait until the sysfs interface is removed in the sysfs write() callback that triggered the removal.
If klp_free_patch_* is moved into module_exit() and not let enable store() to kill kobjects, all kobjects can be deleted in module_exit(), then wait_for_completion(patch->finish) may be removed, also wq isn't required for the async cleanup.
It sounds like a nice cleanup. If we combine kobject_del() to prevent any show()/store() accesses and free everything later in module_exit(), it could work. If I am not missing something around how we maintain internal lists of live patches and their modules.
Thanks
Miroslav