> Unfortunately all that patch and the Linux kernel itself is GPLv2 in fact, not GPLv3. So it is because it is not protected against patent attacks.
GPLv2 patent licensing is 'implicant', not 'explicit' like it is under the GPLv3. Microsoft is given you permission to use the code under the terms of the GPL and as long as you use it under those terms then you'll be fine.
If I gave you a bunch of code, said your allowed to use it on a commercial product, then after you released the product turn around and sue you for patent violations based on the code I gave you... then that is something that would not stand up in court.
> I hope the GNU Hurd kernel will be licensed under GPLv3 _or later_ so we do not have this problem in future.
It has been under development for 19 years and has only managed to achieve the most basic compatibility with real computers.. at which point it was scrapped and started over again with a new Microkernel core. Started off with Mach, then onto L4, then possibly onto Coyotos (too bad Microsoft bought out the developer for that Microkernel) and possibly other L4 variants or Viengoos thingie.
I think that at point we have a better chance that USA will dissolve it's patent system then HURD ever being competitive with Linux.