Don't hog task queue while waiting for exec process

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

supervisor/exit.go

@@ -73,6 +73,11 @@ func (s *Supervisor) execExit(t *ExecExitTask) error {
 	if err := container.RemoveProcess(t.PID); err != nil {
 		logrus.WithField("error", err).Error("containerd: find container for pid")
 	}
+	// If the exec spawned children which are still using its IO
+	// waiting here will block until they die or close their IO
+	// descriptors.
+	// Hence, we use a go routine to avoid block all other operations
+	go func() {
 		t.Process.Wait()
 		s.notifySubscribers(Event{
 			Timestamp: time.Now(),
@@ -81,5 +86,6 @@ func (s *Supervisor) execExit(t *ExecExitTask) error {
 			PID:       t.PID,
 			Status:    t.Status,
 		})
+	}()
 	return nil
 }