reproduce:
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=bdb4d100afe9818aebd1d98ced575c5ef143456c
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout bdb4d100afe9818aebd1d98ced575c5ef143456c
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 olddefconfig
        make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash LDFLAGS=-z max-page-size=0x200000  ./ arch/x86/kernel/ arch/x86/lib/ arch/x86/mm/ drivers/firmware/ drivers/tty/ fs/ init/ kernel/ lib/