On 07/10, Eric W. Biederman wrote: > > Now that we can make the distinction use PIDTYPE_TGID rather than > PIDTYPE_PID.
Wai, wait, this doesn't look right... > There is no immediate effect as they point point at the > same task, How so? pid_task(pid, PIDTYPE_TGID) will return NULL unless this pid is actually a group leader's pid, > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -1315,7 +1315,7 @@ int kill_pid_info(int sig, struct siginfo *info, struct > pid *pid) > > for (;;) { > rcu_read_lock(); > - p = pid_task(pid, PIDTYPE_PID); > + p = pid_task(pid, PIDTYPE_TGID); > if (p) > error = group_send_sig_info(sig, info, p); So, currently kill(pid_nr) always works, even if pid_nr is a sub-thread's tid. After this change kill(2) will always fail with -ESRCH in this case. Or I am totally confused? > --- a/kernel/time/posix-timers.c > +++ b/kernel/time/posix-timers.c > @@ -347,12 +347,11 @@ int posix_timer_event(struct k_itimer *timr, int > si_private) > */ > timr->sigq->info.si_sys_private = si_private; > > + shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID); > rcu_read_lock(); > - task = pid_task(timr->it_pid, PIDTYPE_PID); > - if (task) { > - shared = !(timr->it_sigev_notify & SIGEV_THREAD_ID); > + task = pid_task(timr->it_pid, shared ? PIDTYPE_TGID : PIDTYPE_PID); This looks fine, afaics without SIGEV_THREAD_ID ->it_pid is alwats task_tgid(). Oleg.