The .config inside UBUNTU linux-headers close CONFIG_DEBUG_INFO=y.
It will make KGTP module will not build with "-g" in UBUNTU that
will make KGTP module doesn't have debug info.
To handle this isssue, update Makefile when build KGTP with "D=1",
export CONFIG_DEBUG_INFO=y to make KGTP module can build with -g in
UBUNTU.