reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a9e849efca4f9c7732ea4a81f13ec96208994b22
        git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
        git fetch --no-tags linus master
        git checkout a9e849efca4f9c7732ea4a81f13ec96208994b22
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        make W=1 O=build_dir ARCH=i386 olddefconfig
        make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/firmware/efi/ drivers/mtd/nand/raw/ drivers/scsi/mpi3mr/ drivers/scsi/mpt3sas/