reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git/commit/?id=0783912db6e30339d55a5dc7eb6a696b440bedb3
        git remote add mark https://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git
        git fetch --no-tags mark randomize-kstack-siphash
        git checkout 0783912db6e30339d55a5dc7eb6a696b440bedb3

        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=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-15.1.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash arch/riscv/kernel/