https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org/thread/ZX4BMSCH27O277YIEHCK457LFSRTK5LF/

Hi Xunlei,

FYI, the error/warning still remains.

tree:   https://github.com/alibaba/cloud-kernel.git linux-next
head:   c3ac3c331d6cc495be9603404799c061d71af44c
commit: 9be0ac2bcbaa1831196a88f5e81ea162811f3418 [11093/12249] alinux: cpuacct: export cpuacct.proc_stat interface
config: x86_64-randconfig-a005-20200927 (attached as .config)
compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 6d374cf78c8a80a0bbfc7ce9bc80b3f183f44c80)
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 x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/alibaba/cloud-kernel/commit/9be0ac2bcbaa1831196a88f5e81ea162811f3418
        git remote add alibaba-cloud https://github.com/alibaba/cloud-kernel.git
        git fetch --no-tags alibaba-cloud linux-next
        git checkout 9be0ac2bcbaa1831196a88f5e81ea162811f3418
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

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 >>):

>> fs/proc/stat.c:48:5: warning: no previous prototype for function 'get_idle_time' [-Wmissing-prototypes]
   u64 get_idle_time(int cpu)
       ^
   fs/proc/stat.c:48:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   u64 get_idle_time(int cpu)
   ^
   static 
>> fs/proc/stat.c:64:5: warning: no previous prototype for function 'get_iowait_time' [-Wmissing-prototypes]
   u64 get_iowait_time(int cpu)
       ^
   fs/proc/stat.c:64:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   u64 get_iowait_time(int cpu)
   ^
   static 
   2 warnings generated.

vim +/get_idle_time +48 fs/proc/stat.c

    47	
  > 48	u64 get_idle_time(int cpu)
    49	{
    50		u64 idle, idle_usecs = -1ULL;
    51	
    52		if (cpu_online(cpu))
    53			idle_usecs = get_cpu_idle_time_us(cpu, NULL);
    54	
    55		if (idle_usecs == -1ULL)
    56			/* !NO_HZ or cpu offline so we can rely on cpustat.idle */
    57			idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
    58		else
    59			idle = idle_usecs * NSEC_PER_USEC;
    60	
    61		return idle;
    62	}
    63	
  > 64	u64 get_iowait_time(int cpu)
    65	{
    66		u64 iowait, iowait_usecs = -1ULL;
    67	
    68		if (cpu_online(cpu))
    69			iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
    70	
    71		if (iowait_usecs == -1ULL)
    72			/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
    73			iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
    74		else
    75			iowait = iowait_usecs * NSEC_PER_USEC;
    76	
    77		return iowait;
    78	}
    79	

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