“A recent post to the lkml began, ‘I’m writing a module under a
proprietary license.’ The debate as to whether or not a kernel
module is a derivative work of the Linux kernel itself and thus
must also be released under the GPL has come up many times. Linus
Torvalds has previously noted that things like drivers that were
originally written for other operating systems that have since been
ported to Linux fall into a gray area as they are ‘clearly not a
derived work of Linux in origin.’ In this most recent case, the
author implied that he was working on an original work claiming,
‘but a module providing its internal state to the userspace doesn’t
need to be based on the kernel code in any way,’ going on to ask,
‘please replace every EXPORT_SYMBOL_GPL with EXPORT_SYMBOL in
fs/sysfs/*.c…'”