Just a quick question on linux licensing here, if I 'borrowed' the linux networking stack and included it in my commercial closed source operating system would this be allowed (or my non-commercial but still closed source OS), do I have to give attribution (I do right?)
Consult a lawyer to be sure, but:
If you use gpl code, then you need at the very least make that code freely available. That means: From *you*. A link to kernel org will not be sufficient.
Also your code needs to be carefully evaluated, what counts as derived work.
Derived work will also be GPL.