tree:   https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git 20210427-sysfs-fix-races-v4
head:   177cab73f0f242ce77398095d9c54d76d7fa46df
commit: 177cab73f0f242ce77398095d9c54d76d7fa46df [3/3] drivers/base/core: refcount kobject and bus on device attribute read / store
config: nios2-randconfig-r004-20210618 (attached as .config)
compiler: nios2-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://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git/commit/?id=177cab73f0f242ce77398095d9c54d76d7fa46df
        git remote add mcgrof-next https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git
        git fetch --no-tags mcgrof-next 20210427-sysfs-fix-races-v4
        git checkout 177cab73f0f242ce77398095d9c54d76d7fa46df
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nios2 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> drivers/base/bus.c:42:18: warning: no previous prototype for 'bus_get' [-Wmissing-prototypes]
      42 | struct bus_type *bus_get(struct bus_type *bus)
         |                  ^~~~~~~
>> drivers/base/bus.c:51:6: warning: no previous prototype for 'bus_put' [-Wmissing-prototypes]
      51 | void bus_put(struct bus_type *bus)
         |      ^~~~~~~


vim +/bus_get +42 drivers/base/bus.c

    34	
    35	#define DRIVER_ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) \
    36		struct driver_attribute driver_attr_##_name =		\
    37			__ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store)
    38	
    39	static int __must_check bus_rescan_devices_helper(struct device *dev,
    40							void *data);
    41	
  > 42	struct bus_type *bus_get(struct bus_type *bus)
    43	{
    44		if (bus) {
    45			kset_get(&bus->p->subsys);
    46			return bus;
    47		}
    48		return NULL;
    49	}
    50	
  > 51	void bus_put(struct bus_type *bus)
    52	{
    53		if (bus)
    54			kset_put(&bus->p->subsys);
    55	}
    56	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org