reproduce (this is a W=1 build):
        git checkout 3a8660878839faadb4f1a6dd72c3179c1df56787
        b4 shazam https://lore.kernel.org/r/20251022-work-namespace-nstree-listns-v2-10-71a588572371@kernel.org

        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=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash kernel/