reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/rgushchin/linux/commit/f6d7d74251a82ec19e7d4e92627a6faf008dca8d
        git remote add rgushchin https://github.com/rgushchin/linux.git
        git fetch --no-tags rgushchin bpfoom.1.3
        git checkout f6d7d74251a82ec19e7d4e92627a6faf008dca8d
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=powerpc SHELL=/bin/bash kernel/