Hi Johannes, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: af7b4801030c07637840191c69eb666917e4135d commit: a30cc14fe49c2d5913caf6b987d7cbd86c5e370b um: Don't use generic barrier.h date: 9 months ago config: um-randconfig-r014-20200607 (attached as .config) compiler: gcc-7 (Ubuntu 7.5.0-6ubuntu2) 7.5.0 reproduce (this is a W=1 build): git checkout a30cc14fe49c2d5913caf6b987d7cbd86c5e370b # save the attached .config to linux build tree make 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 <<): /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x22): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x2f): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x3c): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x49): undefined reference to `X86_FEATURE_XMM2' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x56): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x63): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x70): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x7d): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x8a): undefined reference to `X86_FEATURE_XMM' /usr/bin/ld: kernel/irq/generic-chip.o:(.altinstructions+0x97): more undefined references to `X86_FEATURE_XMM' follow collect2: error: ld returned 1 exit status --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org