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For .name, this field is NULL if the component is matched by .of_node instead. In fact, only one of these fields may be set. This caused a NULL pointer dereference on MediaTek MT8195 and MT8188 platforms with the subsequent conversion to snd_soc_dlc_is_dummy() in their machine drivers. The codecs are all matches through the device tree, so their .name fields are empty. For .dai_name, there are cases where this field is empty, such as for the following component definitions: #define COMP_EMPTY() { } #define COMP_PLATFORM(_name) { .name =3D _name } #define COMP_AUX(_name) { .name =3D _name } #define COMP_CODEC_CONF(_name) { .name =3D _name } Or the single link CPU DAI case in the simple audio card family, as covered by simple_util_canonicalize_cpu(), in which the .dai_name field is explicitly cleared. To fix this, check the validity of the fields before using them in string comparison. Fixes: 3e021f3b8115 ("ASoC: soc-utils: add snd_soc_dlc_is_dummy()") Cc: Kuninori Morimoto Signed-off-by: Chen-Yu Tsai Acked-by: Kuninori Morimoto --- sound/soc/soc-utils.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/sound/soc/soc-utils.c b/sound/soc/soc-utils.c index a1bcc852a6de..c8adfff826bd 100644 --- a/sound/soc/soc-utils.c +++ b/sound/soc/soc-utils.c @@ -267,8 +267,8 @@ int snd_soc_dlc_is_dummy(struct snd_soc_dai_link_compon= ent *dlc) if (dlc =3D=3D &snd_soc_dummy_dlc) return true; =20 - if (strcmp(dlc->name, snd_soc_dummy_dlc.name) =3D=3D 0 || - strcmp(dlc->dai_name, snd_soc_dummy_dlc.dai_name) =3D=3D 0) + if ((dlc->name && strcmp(dlc->name, snd_soc_dummy_dlc.name) = =3D=3D 0) || + (dlc->dai_name && strcmp(dlc->dai_name, snd_soc_dummy_dlc.dai_name) = =3D=3D 0)) return true; =20 return false; --=20 2.49.0.1101.gccaa498523-goog