If they are just small wear holes use some Quick Grip, not only seals the hole but can act as a Chaff pad as well ..... Or if bigger or tears get a canvas needle and some sailmakers thread and do some tight figure 8 stitches over the hole then rub with some soap or beeswax, really small holes can be fixed using normal needle and thread ......... Thats how I would fix Tents, Truck tarps and Drizabone coats ... if its an actual hole where you can't get the edges together you will have to use a patch but they do have some tape stuff you can use, though Im a old style sailmaker repair sort of fella.