"The Linux Kernel is provided under the terms of the GNU General Public License version 2 only (GPL-2.0), as provided in LICENSES/preferred/GPL-2.0, with an explicit syscall exception described in LICENSES/exceptions/Linux-syscall-note, as described in the COPYING file."
In other words, the Linux kernel isn't pure gplv2, but comes with an exception in order to allow linking.
https://github.com/torvalds/linux/blob/master/Documentation/...
"The Linux Kernel is provided under the terms of the GNU General Public License version 2 only (GPL-2.0), as provided in LICENSES/preferred/GPL-2.0, with an explicit syscall exception described in LICENSES/exceptions/Linux-syscall-note, as described in the COPYING file."
In other words, the Linux kernel isn't pure gplv2, but comes with an exception in order to allow linking.