[pulseaudio-discuss] [PATCH] loopback: Fix crash if Max Request change at unload

[Arun Raghavan]

On Fri, 2012-02-10 at 17:39 +0100, Frédéric Dalleau wrote:
> Module-bluetooth-policy can load and unload module-loopback on demand.
> Sometimes if there is an error, module-loopback can be unloaded early.
> When module-loopback is loaded, it attaches a sink and the sink
> calls sink_input_update_max_request for which there is a callback.
> In this callback, module-loopback will queue a message in order to
> process it from main thread. The message is queued in the sink
> thread queue.
> 
> There is a possibility that this message is not processed if unload
> has been requested. When this happens, the message
> is still in the queue, and will eventually be processed. This triggers
> segfault because the message carries a pointer to the no
> longer existing sink input.
> 
> The fix is inspired by pa_thread_mq does for registering a thread specific
> message queue. The idea is to create a module-specific queue. Any pending
>  message at unload will be flushed without processing.
> ---

Thanks for the very nice, detailed analysis in the log message. Would
this also be fixed by doing a pa_asycmsgq_flush() on the thread's outq
during teardown?

Cheers,
Arun