tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: 92477dd1faa650e50bd3bb35a6c0b8d09198cc35 commit: 64b302ab66c5965702693e79690823ca120288b9 x86/vdso: Provide vdso_data offset on vvar_page date: 1 year, 8 months ago config: i386-randconfig-r036-20210927 (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/?id=64b302ab66c5965702693e79690823ca120288b9 git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 64b302ab66c5965702693e79690823ca120288b9 # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> arch/x86/entry/vdso/vma.c:32:19: warning: no previous prototype for 'arch_get_vdso_data' [-Wmissing-prototypes] 32 | struct vdso_data *arch_get_vdso_data(void *vvar_page) | ^~~~~~~~~~~~~~~~~~ vim +/arch_get_vdso_data +32 arch/x86/entry/vdso/vma.c 31 > 32 struct vdso_data *arch_get_vdso_data(void *vvar_page) 33 { 34 return (struct vdso_data *)(vvar_page + _vdso_data_offset); 35 } 36 #undef EMIT_VVAR 37 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org