reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # install riscv cross compiling tool for clang build
        # apt-get install binutils-riscv64-linux-gnu
        # https://github.com/kdave/btrfs-devel/commit/96da40206d7e27b71b58cca6209a17a61acff478
        git remote add kdave-btrfs-devel https://github.com/kdave/btrfs-devel.git
        git fetch --no-tags kdave-btrfs-devel dev/param-const
        git checkout 96da40206d7e27b71b58cca6209a17a61acff478
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=riscv SHELL=/bin/bash fs/btrfs/