reproduce (this is a W=1 build):
        git clone https://github.com/intel/lkp-tests.git ~/lkp-tests
        git remote add rust https://github.com/Rust-for-Linux/linux
        git fetch rust rust-next
        git checkout rust/rust-next
        b4 shazam https://lore.kernel.org/r/81647cce3b8e7139af47f20dbeba184b7a89b0cc.1752573305.git.zhuhui@kylinos.cn
        # 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 drivers/tty/serial/8250/ mm/