reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/btrfs/linux/commit/42b0edc3c17de54ab03c66a3bf6232e27ec88eb1
        git remote add btrfs https://github.com/btrfs/linux.git
        git fetch --no-tags btrfs dev/param-const-manual
        git checkout 42b0edc3c17de54ab03c66a3bf6232e27ec88eb1
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-19 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash fs/btrfs/