reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        # https://github.com/cornelisnetworks/linux/commit/42ab16807bc676eb7d0d33ede83d44aca682abf2
        git remote add cornelisnetworks https://github.com/cornelisnetworks/linux.git
        git fetch --no-tags cornelisnetworks for-upstream-20250903-1
        git checkout 42ab16807bc676eb7d0d33ede83d44aca682abf2
        # 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/infiniband/sw/rdmavt/