@@ -1279,10 +1279,12 @@ static int mt8188_mt6359_soc_card_probe(struct mtk_soc_card_data *soc_card_data,
for_each_card_prelinks(card, i, dai_link) {
if (strcmp(dai_link->name, "DPTX_BE") == 0) {
- if (strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
+ if (dai_link->num_codecs &&
+ strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
dai_link->init = mt8188_dptx_codec_init;
} else if (strcmp(dai_link->name, "ETDM3_OUT_BE") == 0) {
- if (strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
+ if (dai_link->num_codecs &&
+ strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
dai_link->init = mt8188_hdmi_codec_init;
} else if (strcmp(dai_link->name, "DL_SRC_BE") == 0 ||
strcmp(dai_link->name, "UL_SRC_BE") == 0) {
@@ -1294,6 +1296,9 @@ static int mt8188_mt6359_soc_card_probe(struct mtk_soc_card_data *soc_card_data,
strcmp(dai_link->name, "ETDM2_OUT_BE") == 0 ||
strcmp(dai_link->name, "ETDM1_IN_BE") == 0 ||
strcmp(dai_link->name, "ETDM2_IN_BE") == 0) {
+ if (!dai_link->num_codecs)
+ continue;
+
if (!strcmp(dai_link->codecs->dai_name, MAX98390_CODEC_DAI)) {
/*
* The TDM protocol settings with fixed 4 slots are defined in
@@ -1099,7 +1099,7 @@ static int mt8192_mt6359_legacy_probe(struct mtk_soc_card_data *soc_card_data)
dai_link->ignore = 0;
}
- if (dai_link->num_codecs && dai_link->codecs[0].dai_name &&
+ if (dai_link->num_codecs &&
strcmp(dai_link->codecs[0].dai_name, RT1015_CODEC_DAI) == 0)
dai_link->ops = &mt8192_rt1015_i2s_ops;
}
@@ -1127,7 +1127,7 @@ static int mt8192_mt6359_soc_card_probe(struct mtk_soc_card_data *soc_card_data,
int i;
for_each_card_prelinks(card, i, dai_link)
- if (dai_link->num_codecs && dai_link->codecs[0].dai_name &&
+ if (dai_link->num_codecs &&
strcmp(dai_link->codecs[0].dai_name, RT1015_CODEC_DAI) == 0)
dai_link->ops = &mt8192_rt1015_i2s_ops;
}
@@ -1380,10 +1380,12 @@ static int mt8195_mt6359_soc_card_probe(struct mtk_soc_card_data *soc_card_data,
for_each_card_prelinks(card, i, dai_link) {
if (strcmp(dai_link->name, "DPTX_BE") == 0) {
- if (strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
+ if (dai_link->num_codecs &&
+ strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
dai_link->init = mt8195_dptx_codec_init;
} else if (strcmp(dai_link->name, "ETDM3_OUT_BE") == 0) {
- if (strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
+ if (dai_link->num_codecs &&
+ strcmp(dai_link->codecs->dai_name, "snd-soc-dummy-dai"))
dai_link->init = mt8195_hdmi_codec_init;
} else if (strcmp(dai_link->name, "DL_SRC_BE") == 0 ||
strcmp(dai_link->name, "UL_SRC1_BE") == 0 ||
@@ -1396,6 +1398,9 @@ static int mt8195_mt6359_soc_card_probe(struct mtk_soc_card_data *soc_card_data,
strcmp(dai_link->name, "ETDM2_OUT_BE") == 0 ||
strcmp(dai_link->name, "ETDM1_IN_BE") == 0 ||
strcmp(dai_link->name, "ETDM2_IN_BE") == 0) {
+ if (!dai_link->num_codecs)
+ continue;
+
if (!strcmp(dai_link->codecs->dai_name, MAX98390_CODEC_DAI)) {
if (!(codec_init & MAX98390_CODEC_INIT)) {
dai_link->init = mt8195_max98390_init;
Following commit 13f58267cda3 ("ASoC: soc.h: don't create dummy Component via COMP_DUMMY()"), COMP_DUMMY() became an array with zero length, and only gets populated with the dummy struct after the card is registered. Since the sound card driver's probe happens before the card registration, accessing any of the members of a dummy component during probe will result in undefined behavior. This can be observed in the mt8188 and mt8195 machine sound drivers. By omitting a dai link subnode in the sound card's node in the Devicetree, the default uninitialized dummy codec is used, and when its dai_name pointer gets passed to strcmp() it results in a null pointer dereference and a kernel panic. In addition to that, set_card_codec_info() in the generic helpers file, mtk-soundcard-driver.c, will populate a dai link with a dummy codec when a dai link node is present in DT but with no codec property. The result is that at probe time, a dummy codec can either be uninitialized with num_codecs = 0, or be an initialized dummy codec, with num_codecs = 1 and dai_name = "snd-soc-dummy-dai". In order to accommodate for both situations, check that num_codecs is not zero before accessing the codecs' fields but still check for the codec's dai name against "snd-soc-dummy-dai" as needed. While at it, also drop the check that dai_name is not null in the mt8192 driver, introduced in commit 4d4e1b6319e5 ("ASoC: mediatek: mt8192: Check existence of dai_name before dereferencing"), as it is actually redundant given the preceding num_codecs != 0 check. Fixes: 13f58267cda3 ("ASoC: soc.h: don't create dummy Component via COMP_DUMMY()") Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com> --- sound/soc/mediatek/mt8188/mt8188-mt6359.c | 9 +++++++-- sound/soc/mediatek/mt8192/mt8192-mt6359-rt1015-rt5682.c | 4 ++-- sound/soc/mediatek/mt8195/mt8195-mt6359.c | 9 +++++++-- 3 files changed, 16 insertions(+), 6 deletions(-) --- base-commit: b852e1e7a0389ed6168ef1d38eb0bad71a6b11e8 change-id: 20241126-asoc-mtk-dummy-panic-1f7961fcecdb Best regards,