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From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
To: "Dan Carpenter" <dan.carpenter@linaro.org>
Cc: linux-sound@vger.kernel.org
Subject: Re: [bug report] ASoC: audio-graph-card2: add Codec2Codec support
Date: Fri, 10 May 2024 08:47:19 +0900	[thread overview]
Message-ID: <877cg2r1iw.wl-kuninori.morimoto.gx@renesas.com> (raw)
In-Reply-To: <241354da-20c4-4ef0-90f7-68d6c4ee13d4@moroto.mountain>


Hi Dan

> > >     1201         struct device_node *ep0 = port_to_endpoint(port0);
> > >     1202         struct device_node *ep1 = port_to_endpoint(port1);
> > >     1203         struct device_node *codec0 = of_graph_get_remote_port(ep0);
> > >     1204         struct device_node *codec1 = of_graph_get_remote_port(ep1);
> > >     1205 
> > > --> 1206         of_node_get(lnk);
> > > 
> > > So this of_node_get() undoes the put.  But if the reference count
> > > dropped to zero then this would be a use afer free.
> > 
> > Thank you for pointing it.
> > 
> > This "lnk" is used as "port0", and of_node_get(lnk) was for it,
> > but this function doesn't call of_node_put(port0).
> > So yes, indeed this of_node_get() is not needed.
> > Let's remove it. 
> 
> No no... of_get_next_child() will drop the reference.  It is needed.
> The point is we should take the reference first before calling
> of_get_next_child().
> 
> Maybe something like this:
> 
> 	struct device_node *port1 = of_get_next_child(ports, of_node_get(lnk));

Oops, oh yes. It need to keep reference.
Thank you for your help, again. I will post fixup patch.


Best regards
---
Renesas Electronics
Ph.D. Kuninori Morimoto

      reply	other threads:[~2024-05-09 23:47 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-05-08 15:14 [bug report] ASoC: audio-graph-card2: add Codec2Codec support Dan Carpenter
2024-05-09  0:13 ` Kuninori Morimoto
2024-05-09  6:49   ` Dan Carpenter
2024-05-09 23:47     ` Kuninori Morimoto [this message]

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