As long as the peanut butter you're feeding your dog does not contain xylitol then the peanut butter is safe for dogs.
The only time the dog cannot eat peanut butter is if the peanut butter you have is made with the ingredient xylitol
The ingredient xylitol is harmful to dos so just make sure the peanut butter contains no xylitol and the dog can safely eat the peanut butter.
Skippy Peanut Butter and the Walmart brands of peanut butter do not contain xylitol so it's safe for the dog to eat.
I feed my dog some peanut butter and it's healthy for them as well due to the protein.