Hi Arnd, FYI, the error/warning still remains. tree: https://github.com/intel/linux-intel-lts.git 4.19/android_r head: 072f407465e8e25a3c2c22590e1ab72ccf335151 commit: 7783c5c8ec0d6781dc180be5fd075f06f90e9cb5 [20723/22631] UPSTREAM: page flags: prioritize kasan bits over last-cpuid config: mips-randconfig-r031-20210409 (attached as .config) compiler: mips64el-linux-gcc (GCC) 9.3.0 reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # https://github.com/intel/linux-intel-lts/commit/7783c5c8ec0d6781dc180be5f... git remote add intel-linux-intel-lts https://github.com/intel/linux-intel-lts.git git fetch --no-tags intel-linux-intel-lts 4.19/android_r git checkout 7783c5c8ec0d6781dc180be5fd075f06f90e9cb5 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=mips 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 >>): In file included from include/linux/mm_types.h:15, from arch/mips/include/asm/vdso.h:14, from arch/mips/include/asm/vdso/vdso.h:28, from arch/mips/include/asm/vdso/gettimeofday.h:16, from include/vdso/datapage.h:114, from lib/vdso/gettimeofday.c:5, from <command-line>: 95 | #error "Not enough bits in page flags" | ^~~~~ In file included from include/vdso/datapage.h:114, from lib/vdso/gettimeofday.c:5, from <command-line>: arch/mips/include/asm/vdso/gettimeofday.h: In function 'clock_gettime_fallback': arch/mips/include/asm/vdso/gettimeofday.h:55:31: error: '__NR_clock_gettime64' undeclared (first use in this function) 55 | register long nr asm("v0") = __NR_clock_gettime64; | ^~~~~~~~~~~~~~~~~~~~ arch/mips/include/asm/vdso/gettimeofday.h:55:31: note: each undeclared identifier is reported only once for each function it appears in arch/mips/include/asm/vdso/gettimeofday.h: In function 'clock_getres_fallback': arch/mips/include/asm/vdso/gettimeofday.h:79:31: error: '__NR_clock_getres_time64' undeclared (first use in this function) 79 | register long nr asm("v0") = __NR_clock_getres_time64; | ^~~~~~~~~~~~~~~~~~~~~~~~ arch/mips/vdso/vgettimeofday.c: At top level: arch/mips/vdso/vgettimeofday.c:14:5: warning: no previous prototype for '__vdso_clock_gettime' [-Wmissing-prototypes] 14 | int __vdso_clock_gettime(clockid_t clock, | ^~~~~~~~~~~~~~~~~~~~ arch/mips/vdso/vgettimeofday.c:28:5: warning: no previous prototype for '__vdso_gettimeofday' [-Wmissing-prototypes] 28 | int __vdso_gettimeofday(struct __kernel_old_timeval *tv, | ^~~~~~~~~~~~~~~~~~~ arch/mips/vdso/vgettimeofday.c:36:5: warning: no previous prototype for '__vdso_clock_getres' [-Wmissing-prototypes] 36 | int __vdso_clock_getres(clockid_t clock_id, | ^~~~~~~~~~~~~~~~~~~ arch/mips/vdso/vgettimeofday.c:42:5: warning: no previous prototype for '__vdso_clock_gettime64' [-Wmissing-prototypes] 42 | int __vdso_clock_gettime64(clockid_t clock, | ^~~~~~~~~~~~~~~~~~~~~~ vim +95 include/linux/page-flags-layout.h 92 93 #if SECTIONS_WIDTH+NODES_WIDTH+ZONES_WIDTH+LAST_CPUPID_WIDTH+KASAN_TAG_WIDTH \ 94 > BITS_PER_LONG - NR_PAGEFLAGS 96 #endif 97 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org