Memleak debugging

[Mathieu Duponchelle]

Hey Florian,

You need to make sure to release all references to elements, for
instance clear self.mixers, self.outputs etc :)

Hope that helps

On Tue, 2022-09-06 at 08:39 +0200, Florian Echtler via gstreamer-devel
wrote:
> Hi everyone,
> 
> I noticed a resource leak in my Python-based WebRTC application after
> extended 
> runtime; it hangs with the repeated error message
> "gst_poll_read_control: 
> assertion 'set != NULL' failed". AFAICT this likely means that too
> many GstBus 
> objects or bus watches are still hanging around.
> 
> I've taken care to cleanup all resources when a client disconnects
> and I've 
> verified this via the debug dot graph; there are no unexpected
> elements or pads 
> hanging around anymore.
> 
> However, when I use the leak tracer, then it complains about a huge
> amount of 
> leaks, including all the elements I supposedly removed (e.g. after 4
> clients 
> have connected and disconnected, the leak tracer shows 4 leaked
> GstWebRTCBin 
> objects).
> 
> Here's a snippet from the code I use to tidy up after a client
> disconnects:
> 
>          # pause the bin
>          self.wrb.bin.set_state(Gst.State.NULL)
> 
>          # pause, unlink, and remove the output buffers
>          logging.debug("  Removing outputs...")
>          for i in self.outputs:
>              out_tee = self.outputs[i]
>              out_tee.set_state(Gst.State.NULL)
>              for p in out_tee.srcpads:
>                  p.unlink(p.get_peer())
>              remove_element(out_tee)
> 
>          # remove the bin
>          logging.debug("  Removing main bin...")
>          remove_element(self.wrb.bin)
> 
> AFAICT, if I stop and remove a bin, then it should deal with its
> internal 
> components on its own, correct? Is there something I'm missing? I did
> not use 
> blocking pad probes here because I don't care about buffers getting
> lost at this 
> point.
> 
> Any hints welcome!
> 
> For reference, the full code is here: 
> https://github.com/floe/surfacestreams/blob/main/client.py#L84-L140
> 
> Thanks and best, Florian
> -- 
> SENT FROM MY DEC VT50 TERMINAL