reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git/commit/?id=a544d9a66bdf20eb25cc40f99e1d09c825b71b26
        git remote add trace https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
        git fetch --no-tags trace for-next
        git checkout a544d9a66bdf20eb25cc40f99e1d09c825b71b26

        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=$HOME/0day COMPILER=gcc-10.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.5.0 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash kernel/trace/