From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Subject: Re: [PATCH v2 2/2] topology: Fix the missing
 referenced elem ptr when merging private data
Date: Fri, 22 Jul 2016 11:16:21 +0900
Message-ID: <579181F5.3090206@sakamocchi.jp>
References: <cover.1469151453.git.mengdong.lin@linux.intel.com>
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To: mengdong.lin@linux.intel.com, alsa-devel@alsa-project.org, broonie@kernel.org
Cc: tiwai@suse.de, mengdong.lin@intel.com, liam.r.girdwood@intel.com, shreyas.nc@intel.com
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On Jul 22 2016 10:47, mengdong.lin@linux.intel.com wrote:
> From: Mengdong Lin <mengdong.lin@linux.intel.com>
>
> tplg_copy_data() should set the valid referenced data element pointer
> on success. The caller will double check this pointer for all kinds of
> references, including controls and data.
>
> Signed-off-by: Mengdong Lin <mengdong.lin@linux.intel.com>
>
> diff --git a/src/topology/data.c b/src/topology/data.c
> index 768fc27..e7793b2 100644
> --- a/src/topology/data.c
> +++ b/src/topology/data.c
> @@ -1078,6 +1078,8 @@ int tplg_copy_data(snd_tplg_t *tplg, struct tplg_elem *elem,
>   	ref_elem->compound_elem = 1;
>   	memcpy(priv->data + old_priv_data_size,
>   	       ref_elem->data->data, priv_data_size);
> +
> +	ref->elem = ref_elem;
>   	return 0;
>   }

Is this really OK when the found topology element has no private data? 
In this case, ref->elem has no assignment at return.

ref_elem = tplg_elem_lookup(&tplg->pdata_list,
                              ref->id, SND_TPLG_TYPE_DATA);
...
/* overlook empty private data */
if (!ref_elem->data || !ref_elem->data->size)
         return 0;
...
ref->elem = ref_elem;
return 0;


Regards

Takashi Sakamoto