reproduce (this is a W=1 build): git clone https://github.com/intel/lkp-tests.git ~/lkp-tests # install um cross compiling tool for clang build # apt-get install binutils-um-linux-gnu git checkout 8cf0b93919e13d1e8d4466eb4080a4c4d9d66d7b b4 shazam https://lore.kernel.org/r/20241008-b4-has_ioport-v8-5-793e68aeadda@linux.ibm.com # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-20 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=um SHELL=/bin/bash drivers/watchdog/