> Documentation of task_get_css() says it always > returns a valid css. This function is used by get_current_misc_cg() to get > the css refernce. > > > /** > * task_get_css - find and get the css for (task, subsys) > * @task: the target task > * @subsys_id: the target subsystem ID > * > * Find the css for the (@task, @subsys_id) combination, increment a > * reference on and return it. This function is guaranteed to return a > * valid css. The returned css may already have been offlined. > */ > static inline struct cgroup_subsys_state * > task_get_css(struct task_struct *task, int subsys_id) Ah, I missed this comment. This confirms my code reading too. > > > If you look at the code of this function, you will see it does not check > NULL either for task_css(). > > So I think we are pretty sure here it's confirmed by this documentation > and testing. Yeah agreed. Thanks.