reproduce (this is a W=1 build):
        # https://github.com/kdave/btrfs-devel/commit/69bb73593025c83c008129a68acd562e97870998
        git remote add kdave-btrfs-devel https://github.com/kdave/btrfs-devel.git
        git fetch --no-tags kdave-btrfs-devel ext/dv/fscrypt
        git checkout 69bb73593025c83c008129a68acd562e97870998

        # clang-23 might not be officially released. Try a lower version if installation fails.
        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=$HOME/0day COMPILER=clang-23 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-23 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/btrfs/