On Thu, Feb 08, 2024 at 03:06:10PM +0100, Oleg Nesterov wrote: > On 02/08, Christian Brauner wrote: > > > > I would also suggest we update the obsolete comment on top of > > pidfd_send_signal() along the lines of: > > Yes, but... > > > + * If the @pidfd refers to a thread-group leader the signal is thread-group > > + * directed. If @pidfd referes to a thread then the signal is thread directed. > > No, this depends on PIDFD_THREAD only. Sorry, yes, that is what I meant to say but obviously wrote unclearly. I mean that if pidfd->f_flags & PIDFD_THREAD then it's thread-directed. That's what I meant by type of pidfd. Not type as in PIDTYPE_PID in struct pid. > > If it is set then the signal is always "thread directed" even if @pidfd refers > to a thread-group leader. > > Otherwise the target task must be a group leader and the signal will be > "thread-group directed". > > Right? Yes, please feel free to update the comment!