Comment 5 for bug 411349

> I think that's probably just the main thread....
Yes, I know; I just gave it as an indication that it seems to do nothing at all.

> Try looking in /proc/<pid>/task for PIDs of the thread(s), and stracing those.
Good tip, I'll try to do that the next time it hangs.

> Thanks for your persistence!
Thanks *you* for helping!