This is different, netfilter had presumable only a single copyright holder (or a few), Harald Welte. This isn't the case with the whole of Linux. For each infginged part, you would have to figure out who the copyright holder is, and ask them to sue.
Why each, and not any? Suing for any infringment should suffice, AFAICS. (Though, as I said, perhaps for lesser damages etc., so it's probably good to get as many and substantial contributors as possible, but I can't see why all would be required.)
You can only sue for the bits you hold the copyright on.
If your position is true, then how about the following scenario (yes, I like to construct scenarios ;-):
Me too. :-)
- E. Vil claims that as not all of the copyright holders of the work he obtained are suing, they cannot sue at all.
Since E. Vil is still violating the copyright of the FSF copyrighted works, they will need to comply, "or else". They can then keep _your_ changes non-free, since you didn't sue.
That's obviously an absurd defense. I suppose you agree.
I spoke about Linux as a whole, not in small parts.
Yes, you talked about "mak[ing] Linux [as a whole] a non-free program". But since this would violate the license of the whole, it would also violate the license of each of its parts (some double-licensed parts perhaps excluded).
And each party would have to come to the table to protect the `whole' work. They can ofcourse come to the table and protect parts of the work.
and only do the minimal to comply with the bits you are infringing on.
So, if the one who sues is Linus Torvalds? You'd have to spend quite some effort to identify and remove hit "bits", and even more replacing them so you get something working again.
Linus' bits are really small in Linux.
And all that only in order to wait for Alan Cox to sue you next (in which will probably a rather simple court decision, given that it will be the same situation applied to the next "few" source lines), etc. And even in the meantime you probably can't do much with your non-free version if you don't want to become liable for damages (probably for intentional violation, at least from the second time). Seems like an even sillier tactic than SCO's, IMHO. IANAL.
Sure, I didn't say it was practical. :-)
Cheers.