Re: [PATCH v2] ASoC: mediatek: mt8195: Add platform entry for ETDM1_OUT_BE dai link

[AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>]

Il 24/06/24 08:12, Chen-Yu Tsai ha scritto:
> Commit e70b8dd26711 ("ASoC: mediatek: mt8195: Remove afe-dai component
> and rework codec link") removed the codec entry for the ETDM1_OUT_BE
> dai link entirely instead of replacing it with COMP_EMPTY(). This worked
> by accident as the remaining COMP_EMPTY() platform entry became the codec
> entry, and the platform entry became completely empty, effectively the
> same as COMP_DUMMY() since snd_soc_fill_dummy_dai() doesn't do anything
> for platform entries.
>
> This causes a KASAN out-of-bounds warning in mtk_soundcard_common_probe()
> in sound/soc/mediatek/common/mtk-soundcard-driver.c:
>
> 	for_each_card_prelinks(card, i, dai_link) {
> 		if (adsp_node && !strncmp(dai_link->name, "AFE_SOF", strlen("AFE_SOF")))
> 			dai_link->platforms->of_node = adsp_node;
> 		else if (!dai_link->platforms->name && !dai_link->platforms->of_node)
> 			dai_link->platforms->of_node = platform_node;
> 	}
>
> where the code expects the platforms array to have space for at least one entry.
>
> Add an COMP_EMPTY() entry so that dai_link->platforms has space.
>
> Fixes: e70b8dd26711 ("ASoC: mediatek: mt8195: Remove afe-dai component and rework codec link")
> Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>

Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>

> ---
> Changes since v1:
> - Reword commit message with more details on how the original commit
>    got things wrong, and what this commit adds and fixes
> ---
>   sound/soc/mediatek/mt8195/mt8195-mt6359.c | 1 +
>   1 file changed, 1 insertion(+)
>
> diff --git a/sound/soc/mediatek/mt8195/mt8195-mt6359.c b/sound/soc/mediatek/mt8195/mt8195-mt6359.c
> index ca8751190520..2832ef78eaed 100644
> --- a/sound/soc/mediatek/mt8195/mt8195-mt6359.c
> +++ b/sound/soc/mediatek/mt8195/mt8195-mt6359.c
> @@ -827,6 +827,7 @@ SND_SOC_DAILINK_DEFS(ETDM2_IN_BE,
>   
>   SND_SOC_DAILINK_DEFS(ETDM1_OUT_BE,
>   		     DAILINK_COMP_ARRAY(COMP_CPU("ETDM1_OUT")),
> +		     DAILINK_COMP_ARRAY(COMP_EMPTY()),
>   		     DAILINK_COMP_ARRAY(COMP_EMPTY()));
>   
>   SND_SOC_DAILINK_DEFS(ETDM2_OUT_BE,