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

[Lin, Mengdong]

> -----Original Message-----
> From: Takashi Sakamoto [mailto:o-takashi at sakamocchi.jp]
> Sent: Friday, July 22, 2016 10:16 AM
> To: mengdong.lin at linux.intel.com; alsa-devel at alsa-project.org;
> broonie at kernel.org
> Cc: tiwai at suse.de; Lin, Mengdong; Girdwood, Liam R; Nc, Shreyas
> Subject: Re: [PATCH v2 2/2] topology: Fix the missing referenced elem ptr
> when merging private data
> 
> 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.

No. This is my mistake. Thanks for finding this bug.

ref->elem should still be assigned for this case. I will make it like this:

/* overlook empty private data */
if (!ref_elem->data || !ref_elem->data->size) {
		ref->elem = ref_elem;
         return 0;
}

Thanks
Mengdong


> /* overlook empty private data */
> if (!ref_elem->data || !ref_elem->data->size)
>          return 0;

> 
> 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