reproduce (this is a W=1 build): git clone https://github.com/intel/lkp-tests.git ~/lkp-tests # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # clang-21 might not be officially released. Try a lower version if installation fails. git checkout 82f2b0b97b36ee3fcddf0f0780a9a0825d52fec3 b4 shazam https://lore.kernel.org/r/20250513100730.12664-34-byungchul@sk.com # save the config file mkdir build_dir && cp config build_dir/.config COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-21 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm olddefconfig COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang-21 ~/lkp-tests/kbuild/make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/dma-buf/