It's not a GCC bug but kind of new feature. Take a look at this changelog entry: gcc-6 (6.2.0-7) unstable; urgency=medium
[ Matthias Klose ]
* Configure with --enable-default-pie and pass -z now when pie is enabled;
on amd64 arm64 armel armhf i386 mips mipsel mips64el ppc64el s390x.
Closes: #835148.
Starting at gcc 6.2.0-7 we must provide "-fno-PIE -fno-PIC" in
beginning of CFLAGS to build kernel successfully.
I'm currently looking for correct way to do this trick.
--
SY,
Konstantin Demin
