Is it possible that spot has been repaired previously? Is there a shadow of a patch under the tear? The canvas looks dry rotted at the site of the tear. That's a bit worrisome.
As Rob suggests, there are a lot of ways to make a repair. Since it looks like a small split, I'd probably fill it with something and paint over it, presuming you have a bit of that paint remaining. The only precaution is to avoid suing a product that has silicon in it.