Hi Ming,

I love your patch! Yet something to improve:

[auto build test ERROR on dennis-percpu/for-next]
[also build test ERROR on linus/master v6.1 next-20221216]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ming-Lei/lib-percpu-refcount-fix-use-after-free-by-late-release/20221214-105440
base:   https://git.kernel.org/pub/scm/linux/kernel/git/dennis/percpu.git for-next
patch link:    https://lore.kernel.org/r/20221214025101.1268437-4-ming.lei%40redhat.com
patch subject: [PATCH 3/3] lib/percpu-refcount: drain ->release() in perpcu_ref_exit()
config: s390-buildonly-randconfig-r006-20221215
compiler: clang version 16.0.0 (https://github.com/llvm/llvm-project 98b13979fb05f3ed288a900deb843e7b27589e58)
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
        # install s390 cross compiling tool for clang build
        # apt-get install binutils-s390x-linux-gnu
        # https://github.com/intel-lab-lkp/linux/commit/29f8a1f1e11734bdaf885ad8e9bcd614c2087fc0
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Ming-Lei/lib-percpu-refcount-fix-use-after-free-by-late-release/20221214-105440
        git checkout 29f8a1f1e11734bdaf885ad8e9bcd614c2087fc0
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=s390 SHELL=/bin/bash

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

All errors (new ones prefixed by >>):

>> lib/percpu-refcount.c:499:47: error: a function declaration without a prototype is deprecated in all versions of C [-Werror,-Wstrict-prototypes]
   wait_queue_head_t *percpu_ref_get_switch_waitq()
                                                 ^
                                                  void
   1 error generated.


vim +499 lib/percpu-refcount.c

   498	
 > 499	wait_queue_head_t *percpu_ref_get_switch_waitq()

-- 
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https://01.org/lkp