On 08/29, sukadev@xxxxxxxxxx wrote: > > +static int ancestor_pid_ns(struct pid_namespace *ns1, struct pid_namespace *ns2) > +{ > + int i; > + struct pid_namespace *tmp; > + > + if (ns1 == NULL || ns2 == NULL) > + return 0; > + > + if (ns1->level >= ns2->level) > + return 0; Looks like this check is not needed, because > + tmp = ns2->parent; > + for (i = tmp->level; i >= ns1->level; i--) { > + if (tmp == ns1) > + return 1; > + tmp = tmp->parent; > + } > + > + return 0; > +} "for ()" does the necessary comparison. The same for descendant_pid_ns(). But do we really need two different functions with 2 arguments? Afaics, we only need is_current_ancestor_pid_ns(tsk). kill_something_info() needs is_current_ancestor_or_the_same_pid_ns(tsk) which could be trivially implemented using the previous one. > --- 2.6.23-rc3-mm1.orig/include/linux/sched.h 2007-08-27 20:04:23.000000000 -0700 > +++ 2.6.23-rc3-mm1/include/linux/sched.h 2007-08-28 23:12:54.000000000 -0700 > @@ -1290,6 +1290,23 @@ static inline pid_t task_ppid_nr_ns(stru > return pid_nr_ns(task_pid(rcu_dereference(tsk->real_parent)), ns); > } > > +static inline struct pid_namespace *pid_active_ns(struct pid *pid) > +{ > + if (pid == NULL) > + return NULL; > + > + return pid->numbers[pid->level].ns; > +} The function itself is racy, this pid can be already freed. Perhaps not a problem currently, afaics it is only used on signal sending path, the receiver is locked (or the task was found under tasklist), and another task is current. > static inline struct pid_namespace *task_active_pid_ns(struct task_struct *tsk) > { > - return tsk->nsproxy->pid_ns; > + /* > + * If task still has its namespaces (i.e it is not exiting) > + * get the pid ns from nsproxy. > + */ > + if (tsk->nsproxy) > + return tsk->nsproxy->pid_ns; Racy. Needs task_lock() or rcu_lock(). Please see below, > + /* > + * If it is exiting but has not been reaped, get pid ns from > + * pid->numbers[]. Otherwise return NULL. > + */ > + return pid_active_ns(task_pid(tsk)); Why can't we just use this chunk and avoid using ->nsproxy? Oleg. _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers