Hi "Rafał, I love your patch! Perhaps something to improve: [auto build test WARNING on driver-core/driver-core-testing] [also build test WARNING on char-misc/char-misc-testing linux/master linus/master v5.16-rc6 next-20211220] [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/Rafa-Mi-ecki/sysfs-add-sysfs_add... base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git aa483f3ce655ed9ee4f32d050d1822eec2d20ada config: x86_64-randconfig-s021-20211219 (https://download.01.org/0day-ci/archive/20211221/202112210456.vwGC0F3M-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce: # apt-get install sparse # sparse version: v0.6.4-dirty # https://github.com/0day-ci/linux/commit/a9802080b6d35af5dfd7ae847a0978e47... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Rafa-Mi-ecki/sysfs-add-sysfs_add_bin_file_to_group/20211220-144856 git checkout a9802080b6d35af5dfd7ae847a0978e47caafd59 # save the config file to linux build tree mkdir build_dir make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=x86_64 SHELL=/bin/bash fs/sysfs/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) Please review and possibly fold the followup patch. --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org