reproduce (this is a W=1 build):
        # https://github.com/isilence/linux/commit/7f35f9df6c2549ded80fd476da928d69c5b29992
        git remote add isilence https://github.com/isilence/linux
        git fetch --no-tags isilence dmabuf-rw/v2-test-unfinished
        git checkout 7f35f9df6c2549ded80fd476da928d69c5b29992

        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests

        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=openrisc olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=openrisc SHELL=/bin/bash