Canelo isn't the type of fighter that if he fights someone you just automatically predict a knockout (ala prime Roy, Tito, Kovalev, Golovkin etc...). If there is an opportunity, there's the possibility that he can stop guys, but it's never a certainty. From what I've seen of Smith, I think he goes the distance but loses a lopsided decision.
Not sure, though Canelo will outweigh him by 20 lbs+ he has slightly more pop then malignaggi. I say no.