Hi Chris, I love your patch! Perhaps something to improve: [auto build test WARNING on jeyu/modules-next] [also build test WARNING on linux/master soc/for-next openrisc/for-next powerpc/next asm-generic/master driver-core/driver-core-testing linus/master v5.13-rc6 next-20210616] [cannot apply to uml/linux-next tip/x86/core] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Chris-Down/printk-Userspace-form... base: https://git.kernel.org/pub/scm/linux/kernel/git/jeyu/linux.git modules-next config: sh-allmodconfig (attached as .config) compiler: sh4-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/0day-ci/linux/commit/819166a91ddffdbf04d0b4e6905a5ab3b... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Chris-Down/printk-Userspace-format-indexing-support/20210617-101450 git checkout 819166a91ddffdbf04d0b4e6905a5ab3b568194f # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=sh If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): kernel/printk/index.c: In function 'pi_show': kernel/printk/index.c:72:2: error: implicit declaration of function 'seq_escape_str'; did you mean 'seq_escape'? [-Werror=implicit-function-declaration] 72 | seq_escape_str(s, src, ESCAPE_ANY | ESCAPE_NAP | ESCAPE_APPEND, "\"\\") | ^~~~~~~~~~~~~~ kernel/printk/index.c:110:3: note: in expansion of macro 'seq_escape_printf_format' 110 | seq_escape_printf_format(s, entry->subsys_fmt_prefix); | ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/index.c:72:38: error: 'ESCAPE_NAP' undeclared (first use in this function); did you mean 'ESCAPE_NP'? 72 | seq_escape_str(s, src, ESCAPE_ANY | ESCAPE_NAP | ESCAPE_APPEND, "\"\\") | ^~~~~~~~~~ kernel/printk/index.c:110:3: note: in expansion of macro 'seq_escape_printf_format' 110 | seq_escape_printf_format(s, entry->subsys_fmt_prefix); | ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/index.c:72:38: note: each undeclared identifier is reported only once for each function it appears in 72 | seq_escape_str(s, src, ESCAPE_ANY | ESCAPE_NAP | ESCAPE_APPEND, "\"\\") | ^~~~~~~~~~ kernel/printk/index.c:110:3: note: in expansion of macro 'seq_escape_printf_format' 110 | seq_escape_printf_format(s, entry->subsys_fmt_prefix); | ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/index.c:72:51: error: 'ESCAPE_APPEND' undeclared (first use in this function); did you mean 'ESCAPE_ANY'? 72 | seq_escape_str(s, src, ESCAPE_ANY | ESCAPE_NAP | ESCAPE_APPEND, "\"\\") | ^~~~~~~~~~~~~ kernel/printk/index.c:110:3: note: in expansion of macro 'seq_escape_printf_format' 110 | seq_escape_printf_format(s, entry->subsys_fmt_prefix); | ^~~~~~~~~~~~~~~~~~~~~~~~ kernel/printk/index.c: At top level: 140 | void pi_create_file(struct module *mod) | ^~~~~~~~~~~~~~ 146 | void pi_remove_file(struct module *mod) | ^~~~~~~~~~~~~~ cc1: some warnings being treated as errors Kconfig warnings: (for reference only) WARNING: unmet direct dependencies detected for SND_ATMEL_SOC_PDC Depends on SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC && HAS_DMA Selected by - SND_ATMEL_SOC_SSC && SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC - SND_ATMEL_SOC_SSC_PDC && SOUND && !UML && SND && SND_SOC && SND_ATMEL_SOC && ATMEL_SSC vim +/pi_create_file +140 kernel/printk/index.c 139 141 { 142 debugfs_create_file(pi_get_module_name(mod), 0444, dfs_index, 143 mod, &dfs_index_fops); 144 } 145 147 { 148 debugfs_remove(debugfs_lookup(pi_get_module_name(mod), dfs_index)); 149 } 150 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org