They cannot revoke the licence under the GPL. If new patches are under a non-Europe licence, then they cannot be combined and redistributed with the existing GP

They cannot revoke the licence under the GPL. If new patches are under a non-Europe licence, then they cannot be combined and redistributed with the existing GPLv2 codebase. There is a provision in section 8 of the GPLv2 that allows excluding certain countries, but it can only be activated in the face of copyright or patent restrictions on the distribution of the software. IANAL, but one approach to activate this provision might be to implement a patented technique within the kernel, for which the patent licence only allows implementations outside the EU.