ASoC: mediatek: mt8192: Check existence of dai_name before dereferencing

Following commit 13f5826 ("ASoC: soc.h: don't create dummy
Component via COMP_DUMMY()"), the dai_name field is only populated for
dummy components after the card is registered. This causes a null
pointer dereference in the mt8192-mt6359 sound card driver's probe
function when searching for a dai_name among all the card's dai links.

Verify that the dai_name is non-null before passing it to strcmp. While
at it, also check that there's at least one codec.

Reported-by: kernelci.org bot <[email protected]>
Closes: https://linux.kernelci.org/test/case/id/6582cd6d992645c680e13478/
Fixes: 13f5826 ("ASoC: soc.h: don't create dummy Component via COMP_DUMMY()")
Signed-off-by: Nícolas F. R. A. Prado <[email protected]>
Link: https://msgid.link/r/[email protected]
Signed-off-by: Mark Brown <[email protected]>

Author: nfraprado

sound/soc/mediatek/mt8192/mt8192-mt6359-rt1015-rt5682.c

@@ -1208,7 +1208,8 @@ static int mt8192_mt6359_dev_probe(struct platform_device *pdev)
 			dai_link->ignore = 0;
 		}
 
-		if (strcmp(dai_link->codecs[0].dai_name, RT1015_CODEC_DAI) == 0)
+		if (dai_link->num_codecs && dai_link->codecs[0].dai_name &&
+		    strcmp(dai_link->codecs[0].dai_name, RT1015_CODEC_DAI) == 0)
 			dai_link->ops = &mt8192_rt1015_i2s_ops;
 
 		if (!dai_link->platforms->name)