I am a Malaysian passport holder, coming into Baiyun with a confirmed boarding pass to Los Angeles,

You are not eligible for the 72 hour free transit because of your nationality, but you may be able to use the 24 hour direct transit if your layover time in Guangzhou is less than 24 hours.
However, if you transit for more than 24 hours at Baiyun airport, you should apply for a transit G type or tourist L type ahead of time.