[lkp@intel.com: [norov:fns 9/23] include/asm-generic/percpu.h:21:44: warning: array subscript 4 is above array bounds of 'long unsigned int[4]']

[Yury Norov <yury.norov@gmail.com>]

Hi Alexander,

I'm working on top of your recent cons bitmap series, and again
received a bug report from LKP regarding one of you patches. Can
you please look at this report?

I tried reproduce it myself, but the build is failed for me:
arch/arc/kernel/entry.S: Assembler messages:
arch/arc/kernel/entry.S:280: Error: operand out of range (260 is not between -256 and 255)
make[2]: *** [scripts/Makefile.build:322: arch/arc/kernel/entry-compact.o] Error 1
make[2]: *** Waiting for unfinished jobs....

If you think it's mis-attributed, we should let LKP people know that
something is wrong on their side.

Thanks,
Yury

----- Forwarded message from kernel test robot <lkp@intel.com> -----

Date: Sat, 2 Jul 2022 08:42:59 +0800
From: kernel test robot <lkp@intel.com>
To: Yury Norov <yury.norov@gmail.com>
Cc: kbuild-all@lists.01.org
Subject: [norov:fns 9/23] include/asm-generic/percpu.h:21:44: warning: array subscript 4 is above array bounds of
	'long unsigned int[4]'

tree:   https://github.com/norov/linux fns
head:   1df9509fd92a58cb37e9a419235823bbb13367de
commit: 3e7e5baaaba78075a7f3a57432609e363bf2a486 [9/23] bitmap: don't assume compiler evaluates small mem*() builtins calls
config: arc-randconfig-r035-20220629 (https://download.01.org/0day-ci/archive/20220702/202207020812.oTFxIVue-lkp@intel.com/config)
compiler: arc-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/norov/linux/commit/3e7e5baaaba78075a7f3a57432609e363bf2a486
        git remote add norov https://github.com/norov/linux
        git fetch --no-tags norov fns
        git checkout 3e7e5baaaba78075a7f3a57432609e363bf2a486
        # 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/

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_sched_domains':
>> 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

^1da177e4c3f415 Linus Torvalds 2005-04-16  20  
a875a69f8b00a38 Ingo Molnar    2006-07-03 @21  #define per_cpu_offset(x) (__per_cpu_offset[x])
acdac87202a4081 travis@sgi.com 2008-01-30  22  #endif
acdac87202a4081 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>

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp

----- End forwarded message -----