Hi Emanuele, Thank you for the patch! Yet something to improve: [auto build test ERROR on char-misc/char-misc-testing] [also build test ERROR on driver-core/driver-core-testing linus/master v5.7-rc1 next-20200414] [cannot apply to security/next-testing] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system. BTW, we also suggest to use '--base' option to specify the base tree in git format-patch, please see https://stackoverflow.com/a/37406982] url: https://github.com/0day-ci/linux/commits/Emanuele-Giuseppe-Esposito/Simpl... base: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git 885a64715fd81e6af6d94a038556e0b2e6deb19c config: arm-mvebu_v7_defconfig (attached as .config) compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # save the attached .config to linux build tree GCC_VERSION=9.3.0 make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kbuild test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): arm-linux-gnueabi-ld: fs/tracefs/inode.o: in function `remove_one': arm-linux-gnueabi-ld: fs/tracefs/inode.o: in function `start_creating.part.0': inode.c:(.text+0x454): undefined reference to `simple_release_fs' arm-linux-gnueabi-ld: fs/tracefs/inode.o: in function `__create_dir': arm-linux-gnueabi-ld: fs/tracefs/inode.o: in function `tracefs_create_file': inode.c:(.text+0x690): undefined reference to `simple_pin_fs' arm-linux-gnueabi-ld: inode.c:(.text+0x75c): undefined reference to `simple_release_fs' arm-linux-gnueabi-ld: fs/tracefs/inode.o: in function `tracefs_remove': inode.c:(.text+0x79c): undefined reference to `simple_pin_fs' arm-linux-gnueabi-ld: inode.c:(.text+0x7c0): undefined reference to `simple_release_fs' --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org