Hi Randy, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 142b507f911c5a502dbb8f603216cb0ea8a79a48 commit: a730af6e3114d549555f4b130c216bad1c3aa80e um: Add 2 missing libs to fix various build errors date: 4 weeks ago config: um-randconfig-r033-20210510 (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/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout a730af6e3114d549555f4b130c216bad1c3aa80e # 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_XMM2" [drivers/mtd/nand/raw/nand.ko] undefined! ERROR: modpost: "X86_FEATURE_XMM" [drivers/misc/altera-stapl/altera-stapl.ko] undefined! ERROR: modpost: "X86_FEATURE_XMM2" [drivers/misc/altera-stapl/altera-stapl.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 - 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