While atomic grouping can prevent this from happening again once you've already found the problem, the real solution is just making sure there is a timeout on y

While atomic grouping can prevent this from happening again once you've already found the problem, the real solution is just making sure there is a timeout on your web process. That way even if you hit catastrophic backtracking, your servers aren't going to be unavailable unless someone is purposely reDOSing them.