reproduce (this is a W=1 build):
        # https://github.com/btrfs/linux/commit/2187ec9166ea7441f551337b91802d65b2283972
        git remote add btrfs https://github.com/btrfs/linux.git
        git fetch --no-tags btrfs pr/1630
        git checkout 2187ec9166ea7441f551337b91802d65b2283972

        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # clang-24 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=$HOME/0day COMPILER=clang-24 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=mips olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-24 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash fs/