Hi Niklas, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: ec2618180c3450d06a6a4ba951d4c9a2c689b517 commit: 5ae6eadfdaf431f47adbdf1754f3b5a5fd638de2 [1527/2770] asm-generic/io.h: warn in inb() and friends with undefined PCI_IOBASE config: um-randconfig-r031-20210513 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout 5ae6eadfdaf431f47adbdf1754f3b5a5fd638de2 # save the attached .config to linux build tree make W=1 W=1 ARCH=um If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>, old ones prefixed by <<): ERROR: modpost: "X86_FEATURE_XMM" [drivers/fpga/altera-pr-ip-core.ko] undefined! ERROR: modpost: "X86_FEATURE_XMM2" [drivers/fpga/altera-pr-ip-core.ko] undefined! ERROR: modpost: "__divdi3" [fs/hostfs/hostfs.ko] undefined! Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for LOCKDEP Depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT && (FRAME_POINTER || MIPS || PPC || S390 || MICROBLAZE || ARM || ARC || X86) Selected by - PROVE_LOCKING && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT - DEBUG_LOCK_ALLOC && DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org