reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace.git/commit/?id=a9bb466c2613f39f468e7ac392dd2e2b611a0544
        git remote add trace https://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
        git fetch --no-tags trace unwind/perf
        git checkout a9bb466c2613f39f468e7ac392dd2e2b611a0544
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash drivers/net/netdevsim/