[alsa-devel] [PATCH v2 2/2] topology: Fix the missing referenced elem ptr when merging private data

[Takashi Sakamoto]

On Jul 22 2016 10:47, mengdong.lin at linux.intel.com wrote:
> From: Mengdong Lin <mengdong.lin at 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 at 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