I am already sleeping. I'll try to reply to other parts of your email tomorrow but I am not sure, I will be very busy with family duties. On 01/23, Tycho Andersen wrote: > > > > __exit_signal(p); > > > > and, do_notify_pidfd() is called before __exit_signal() which does > > __unhash_process() -> detach_pid(PIDTYPE_PID). > > > > Doesn't this mean that pidfd_poll() can hang? thread_group_exited() > > won't return true after do_notify_pidfd() above, not to mention that > > thread_group_empty() is not possible if !thread_group_leader(). > > I was wondering about this too, but the test_non_tgl_poll_exit test in > the next patch tests exactly this and works as expected. Well, if release_task() completes __exit_signal() before the woken task does thread_group_exited(), pid_task(PIDTYPE_PID) will return 0 and pidfd_poll() won't hang. But to be honest I can't understand test_non_tgl_poll_exit() at all. I don't even understand why the process/thread created by fork_task_with_thread() should ever exit. And why it creates the "writer" child... Never mind, too late for me to read the code. Oleg.
