On Sun, 2022-03-27 at 16:17 +0800, Xiaomeng Tong wrote:
> The bug is here:
> mt8195_etdm_hw_params_fixup(runtime, params);
>
> For the for_each_card_rtds(), just like list_for_each_entry(),
> the list iterator 'runtime' will point to a bogus position
> containing HEAD if the list is empty or no element is found.
> This case must be checked before any use of the iterator,
> otherwise it will lead to a invalid memory access.
>
> To fix the bug, use a new variable 'iter' as the list iterator,
> while use the original variable 'runtime' as a dedicated poin
> ter
> to point to the found element.
Hi Xiaomeng,
About this bug, I think it won't happen anymore.
mt8195_dai_link_fixup() is only assigned when the corresponding
snd_soc_pcm_runtime is found
in mt8195_mt6359_rt1019_rt5682_late_probe().
On the other hand, runtime is not used in the body of
mt8195_etdm_hw_params_fixup().
That's why I think the problem doesn't exist.
If I misunderstood the problem you pointed out, please correct me.
Thanks,
Trevor
>
> Cc: stable@xxxxxxxxxxxxxxx
> Fixes: 3d00d2c07f04f ("ASoC: mediatek: mt8195: add sof support on
> mt8195-mt6359-rt1019-rt5682")
> Signed-off-by: Xiaomeng Tong <xiam0nd.tong@xxxxxxxxx>
> ---
> .../mediatek/mt8195/mt8195-mt6359-rt1019-rt5682.c | 14 ++++++++--
> ----
> 1 file changed, 8 insertions(+), 6 deletions(-)
>
> diff --git a/sound/soc/mediatek/mt8195/mt8195-mt6359-rt1019-rt5682.c
> b/sound/soc/mediatek/mt8195/mt8195-mt6359-rt1019-rt5682.c
> index 29c2d3407cc7..dc91877e4c3c 100644
> --- a/sound/soc/mediatek/mt8195/mt8195-mt6359-rt1019-rt5682.c
> +++ b/sound/soc/mediatek/mt8195/mt8195-mt6359-rt1019-rt5682.c
> @@ -814,7 +814,7 @@ static int mt8195_dai_link_fixup(struct
> snd_soc_pcm_runtime *rtd,
> {
> struct snd_soc_card *card = rtd->card;
> struct snd_soc_dai_link *sof_dai_link = NULL;
> - struct snd_soc_pcm_runtime *runtime;
> + struct snd_soc_pcm_runtime *runtime = NULL, *iter;
> struct snd_soc_dai *cpu_dai;
> int i, j, ret = 0;
>
> @@ -824,16 +824,17 @@ static int mt8195_dai_link_fixup(struct
> snd_soc_pcm_runtime *rtd,
> if (strcmp(rtd->dai_link->name, conn->normal_link))
> continue;
>
> - for_each_card_rtds(card, runtime) {
> - if (strcmp(runtime->dai_link->name, conn-
> >sof_link))
> + for_each_card_rtds(card, iter) {
> + if (strcmp(iter->dai_link->name, conn-
> >sof_link))
> continue;
>
> - for_each_rtd_cpu_dais(runtime, j, cpu_dai) {
> + for_each_rtd_cpu_dais(iter, j, cpu_dai) {
> if (cpu_dai->stream_active[conn-
> >stream_dir] > 0) {
> - sof_dai_link = runtime-
> >dai_link;
> + sof_dai_link = iter->dai_link;
> break;
> }
> }
> + runtime = iter;
> break;
> }
>
> @@ -845,7 +846,8 @@ static int mt8195_dai_link_fixup(struct
> snd_soc_pcm_runtime *rtd,
>
> if (!strcmp(rtd->dai_link->name, "ETDM2_IN_BE") ||
> !strcmp(rtd->dai_link->name, "ETDM1_OUT_BE")) {
> - mt8195_etdm_hw_params_fixup(runtime, params);
> + if (runtime)
> + mt8195_etdm_hw_params_fixup(runtime, params);
> }
>
> return ret;
