+ /*
+ * we are under tasklist_lock here so our parent is tied to
+ * us and cannot exit and release its namespace.
+ *
+ * the only it can is to switch its nsproxy with sys_unshare,
+ * bu uncharing pid namespaces is not allowed, so we'll always
+ * see relevant namespace
+ *
+ * write_lock() currently calls preempt_disable() which is the
+ * same as rcu_read_lock(), but according to Oleg, this is not
+ * correct to rely on this
+ */
+ rcu_read_lock();
+ info.si_pid = task_pid_nr_ns(tsk, tsk->parent->nsproxy->pid_ns);
+ rcu_read_unlock();
+