[alobakin:bitops 8/9] include/asm-generic/percpu.h:21:44: warning: array subscript 4 is above array bounds of 'long unsigned int[4]'

[alobakin:bitops 8/9] include/asm-generic/percpu.h:21:44: warning: array subscript 4 is above array bounds of 'long unsigned int[4]'

[kernel test robot]

tree:   https://github.com/alobakin/linux bitops
head:   3d9705b33014389e95ff8ac2eeadd081934aa571
commit: 45be1aaa8e3d90c437780823a2824e53fd13a867 [8/9] bitmap: don't assume compiler evaluates small mem*() builtins calls
config: arc-randconfig-c024-20220625
compiler: arceb-elf-gcc (GCC) 11.3.0
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://github.com/alobakin/linux/commit/45be1aaa8e3d90c437780823a2824e53fd13a867
        git remote add alobakin https://github.com/alobakin/linux
        git fetch --no-tags alobakin bitops
        git checkout 45be1aaa8e3d90c437780823a2824e53fd13a867
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.3.0 make.cross W=1 O=build_dir ARCH=arc SHELL=/bin/bash kernel/sched/ kernel/trace/ mm/

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

All warnings (new ones prefixed by >>):

   In file included from include/linux/compiler_types.h:93,
                    from <command-line>:
   kernel/sched/topology.c: In function 'build_overlap_sched_groups':
>> include/asm-generic/percpu.h:21:44: warning: array subscript 4 is above array bounds of 'long unsigned int[4]' [-Warray-bounds]
      21 | #define per_cpu_offset(x) (__per_cpu_offset[x])
   include/linux/compiler-gcc.h:35:33: note: in definition of macro 'RELOC_HIDE'
      35 |         (typeof(ptr)) (__ptr + (off));                                  \
         |                                 ^~~
   include/linux/percpu-defs.h:236:9: note: in expansion of macro 'SHIFT_PERCPU_PTR'
     236 |         SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)));                 \
         |         ^~~~~~~~~~~~~~~~
   include/linux/percpu-defs.h:236:33: note: in expansion of macro 'per_cpu_offset'
     236 |         SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)));                 \
         |                                 ^~~~~~~~~~~~~~
   kernel/sched/topology.c:969:20: note: in expansion of macro 'per_cpu_ptr'
     969 |         sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);
         |                    ^~~~~~~~~~~
   In file included from ./arch/arc/include/generated/asm/percpu.h:1,
                    from include/linux/irqflags.h:17,
                    from include/linux/rcupdate.h:26,
                    from include/linux/rculist.h:11,
                    from include/linux/sched/signal.h:5,
                    from include/linux/sched/cputime.h:5,
                    from kernel/sched/build_utility.c:13:
   include/asm-generic/percpu.h:19:22: note: while referencing '__per_cpu_offset'
      19 | extern unsigned long __per_cpu_offset[NR_CPUS];
         |                      ^~~~~~~~~~~~~~~~


vim +21 include/asm-generic/percpu.h

^1da177e4c3f41 Linus Torvalds 2005-04-16  20  
a875a69f8b00a3 Ingo Molnar    2006-07-03 @21  #define per_cpu_offset(x) (__per_cpu_offset[x])
acdac87202a408 travis@sgi.com 2008-01-30  22  #endif
acdac87202a408 travis@sgi.com 2008-01-30  23  

:::::: The code at line 21 was first introduced by commit
:::::: a875a69f8b00a38b4f40d9632a4fc71a159f0e0d [PATCH] lockdep: add per_cpu_offset()

:::::: TO: Ingo Molnar <mingo@elte.hu>
:::::: CC: Linus Torvalds <torvalds@g5.osdl.org>

-- 
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