reproduce (this is a W=1 build):
        git remote add jack-fs https://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs.git
        git fetch jack-fs for_next
        git checkout jack-fs/for_next
        b4 shazam https://lore.kernel.org/r/20251203045048.2463502-1-vivek.balachandhar@gmail.com

        # clang-22 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=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-22 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=hexagon SHELL=/bin/bash fs/ext2/