[pulseaudio-discuss] [PATCH] Fix crash on jack server shutdown

[David Henningsson]

Lennart Poettering wrote:
> On Tue, 23.03.10 00:36, David Henningsson (launchpad.web at epost.diwic.se) wrote:
> 
>>> What is missing is that the jack loop does not depend on the PA sink to
>>> be around resp. the PA IO loop doesn't call into jack when it is
>>> dead. If either of that is implemented (and then destruction order
>>> matches this) the problem is fixed.
>>>
>>> Also, what applies to m-jack-sink needs fixing in m-jack-source, too.
>> Good points. I admit to not having checked properly whether
>> pa_sink_unlink and pa_sink_render_full can be called in parallell, I see
>> now that they shouldn't.
> 
> Calling _unlink() and _render_full() at the same time is actually
> fine. _unlink() will send a msg to the IO thread to shut down the sink
> and will synchronously wait for it. _render_full() is called from the IO
> thread. Since the msg dispatching and the _render_full() are run from
> the same thread and hence are serialized there is no problem here.

Oh, so pa_sink_unlink does synchronize with the IO thread. But then I
don't see the "new" race? What call into pa would be a problem after the
sink has been unlinked? It can't be sink rendering, as
u->sink->thread_info.state != PA_SINK_RUNNING at that point, so the
module will just write silence (and not call into pa).

// David