With a name like 'Dirty Frag', I'm guessing this is another memory fragmentation or page cache trick similar to Dirty Pipe?

From TFA:

> Dirty Frag belongs to the same class as Dirty Pipe and Copy Fail. However, while Dirty Pipe overwrites struct pipe_buffer, Dirty Frag overwrites the frag of struct sk_buff

So yup, Dirty Pipe is specifically mentioned.