He might be making reference to linking closed-source to the Linux GPL components... which is, technically, illegal but Torvalds has already pointed out that he has no intention to enforce that. Personally, I'm on Torvald's side of that argument with regard to the Linux kernel--but Nokia HAS abused it in a way that makes them particularly hostile to customers and to the community that wants to fix problems and extend the capabilities of the kernel (much like Tivo, who ended up being the company that ended up making 'Tivoization' a coined term for such open-core abuses such a well-illustrated problem now).