Playlist subitem callback lock inversion
- When a subitem is added to the input item of a playlist item:
- vlc_event_send() takes the event manager event sending lock,
- vlc_event_send() takes the event manager object lock,
- vlc_event_send() releases the event manager object lock,
- the playlist callback takes the playlist lock,
- ...
- When a playlist item is deleted:
- The caller has the playlist lock since playlist_ItemRelease() asserts it,
- vlc_event_detach() takes the event manager event sending lock,
- vlc_event_detach() takes the event manager object lock.
There is a lock inversion between the input item's event manager's event sending lock and the playlist lock.