From the tarball COPYING file: "the only valid version of the GPL as far as the kernel is concerned is _this_ particular version of the license (ie v2, not v2.2 or v3.x or whatever), unless explicitly otherwise stated. -Linus Torvalds"
Which is identical to kernel.org: https://www.kernel.org/pub/linux/kernel/COPYING
That section was discussed at https://lkml.org/lkml/2006/1/25/273 where 2006-Linus doesn't see GPLv3 ever happening.
From the tarball COPYING file: "the only valid version of the GPL as far as the kernel is concerned is _this_ particular version of the license (ie v2, not v2.2 or v3.x or whatever), unless explicitly otherwise stated. -Linus Torvalds"
Which is identical to kernel.org: https://www.kernel.org/pub/linux/kernel/COPYING
That section was discussed at https://lkml.org/lkml/2006/1/25/273 where 2006-Linus doesn't see GPLv3 ever happening.