[PATCH] ASoC: topology: Perform component check upfront

[Sridharan, Ranjani]

On Thu, Mar 12, 2020 at 3:14 AM Amadeusz Sławiński <
amadeuszx.slawinski at linux.intel.com> wrote:

> Function soc_tplg_dbytes_create(), calls soc_tplg_init_kcontrol() to
> perform additional driver specific initialization. While
> soc_tplg_init_kcontrol() ensures that component is valid before invoking
> ops->control_load, there is no such check at the end of
> soc_tplg_dbytes_create() where list_add() is used.
>
> Also in quite a few places, there is reference of tplg->comp->dapm or
> tplg->comp->card, without any checks for tplg->comp.
>
> In consequence of the above this may lead to referencing NULL pointer.
>
> This allows for removal of now unnecessary checks.
>
> Signed-off-by: Amadeusz Sławiński <amadeuszx.slawinski at linux.intel.com>
> ---
>  sound/soc/soc-topology.c | 22 +++++++++++++---------
>  1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/sound/soc/soc-topology.c b/sound/soc/soc-topology.c
> index 575da6aba807..66958c57d884 100644
> --- a/sound/soc/soc-topology.c
> +++ b/sound/soc/soc-topology.c
> @@ -251,7 +251,7 @@ static int soc_tplg_vendor_load_(struct soc_tplg *tplg,
>  {
>         int ret = 0;
>
> -       if (tplg->comp && tplg->ops && tplg->ops->vendor_load)
> +       if (tplg->ops && tplg->ops->vendor_load)
>                 ret = tplg->ops->vendor_load(tplg->comp, tplg->index, hdr);
>         else {
>                 dev_err(tplg->dev, "ASoC: no vendor load callback for ID
> %d\n",
> @@ -283,7 +283,7 @@ static int soc_tplg_vendor_load(struct soc_tplg *tplg,
>  static int soc_tplg_widget_load(struct soc_tplg *tplg,
>         struct snd_soc_dapm_widget *w, struct snd_soc_tplg_dapm_widget
> *tplg_w)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->widget_load)
> +       if (tplg->ops && tplg->ops->widget_load)
>                 return tplg->ops->widget_load(tplg->comp, tplg->index, w,
>                         tplg_w);
>
> @@ -295,7 +295,7 @@ static int soc_tplg_widget_load(struct soc_tplg *tplg,
>  static int soc_tplg_widget_ready(struct soc_tplg *tplg,
>         struct snd_soc_dapm_widget *w, struct snd_soc_tplg_dapm_widget
> *tplg_w)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->widget_ready)
> +       if (tplg->ops && tplg->ops->widget_ready)
>                 return tplg->ops->widget_ready(tplg->comp, tplg->index, w,
>                         tplg_w);
>
> @@ -307,7 +307,7 @@ static int soc_tplg_dai_load(struct soc_tplg *tplg,
>         struct snd_soc_dai_driver *dai_drv,
>         struct snd_soc_tplg_pcm *pcm, struct snd_soc_dai *dai)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->dai_load)
> +       if (tplg->ops && tplg->ops->dai_load)
>                 return tplg->ops->dai_load(tplg->comp, tplg->index,
> dai_drv,
>                         pcm, dai);
>
> @@ -318,7 +318,7 @@ static int soc_tplg_dai_load(struct soc_tplg *tplg,
>  static int soc_tplg_dai_link_load(struct soc_tplg *tplg,
>         struct snd_soc_dai_link *link, struct snd_soc_tplg_link_config
> *cfg)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->link_load)
> +       if (tplg->ops && tplg->ops->link_load)
>                 return tplg->ops->link_load(tplg->comp, tplg->index, link,
> cfg);
>
>         return 0;
> @@ -327,7 +327,7 @@ static int soc_tplg_dai_link_load(struct soc_tplg
> *tplg,
>  /* tell the component driver that all firmware has been loaded in this
> request */
>  static void soc_tplg_complete(struct soc_tplg *tplg)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->complete)
> +       if (tplg->ops && tplg->ops->complete)
>                 tplg->ops->complete(tplg->comp);
>  }
>
> @@ -684,7 +684,7 @@ EXPORT_SYMBOL_GPL(snd_soc_tplg_widget_bind_event);
>  static int soc_tplg_init_kcontrol(struct soc_tplg *tplg,
>         struct snd_kcontrol_new *k, struct snd_soc_tplg_ctl_hdr *hdr)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->control_load)
> +       if (tplg->ops && tplg->ops->control_load)
>                 return tplg->ops->control_load(tplg->comp, tplg->index, k,
>                         hdr);
>
> @@ -1174,7 +1174,7 @@ static int soc_tplg_kcontrol_elems_load(struct
> soc_tplg *tplg,
>  static int soc_tplg_add_route(struct soc_tplg *tplg,
>         struct snd_soc_dapm_route *route)
>  {
> -       if (tplg->comp && tplg->ops && tplg->ops->dapm_route_load)
> +       if (tplg->ops && tplg->ops->dapm_route_load)
>                 return tplg->ops->dapm_route_load(tplg->comp, tplg->index,
>                         route);
>
> @@ -2564,7 +2564,7 @@ static int soc_tplg_manifest_load(struct soc_tplg
> *tplg,
>         }
>
>         /* pass control to component driver for optional further init */
> -       if (tplg->comp && tplg->ops && tplg->ops->manifest)
> +       if (tplg->ops && tplg->ops->manifest)
>                 ret = tplg->ops->manifest(tplg->comp, tplg->index,
> _manifest);
>
>         if (!abi_match) /* free the duplicated one */
> @@ -2736,6 +2736,10 @@ int snd_soc_tplg_component_load(struct
> snd_soc_component *comp,
>         struct soc_tplg tplg;
>         int ret;
>
> +       /* component needs to exist to keep and reference data while
> parsing */
> +       if (!comp)
> +               return -EINVAL;
> +

Amadeusz,

Thanks for this change. I agree that the checks for tplg->comp in the above
functions should be removed but is the check here really necessary at all?
snd_soc_tplg_component_load() is typically called when a component is
probed. Can it ever be null at all if it is getting probed?

Thanks,
Ranjani