Re: [PATCH] lib: typecheck: initialize const variable to avoid Clang warning

[kernel test robot]

Hi hamjin,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v7.0-rc5 next-20260324]
[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/hamjin/lib-typecheck-initialize-const-variable-to-avoid-Clang-warning/20260315-165617
base:   linus/master
patch link:    https://lore.kernel.org/r/tencent_274FD06231C70768C2C28FD13673A24C2B08%40qq.com
patch subject: [PATCH] lib: typecheck: initialize const variable to avoid Clang warning
config: s390-allnoconfig (https://download.01.org/0day-ci/archive/20260325/202603252009.z5G8iyl7-lkp@xxxxxxxxx/config)
compiler: clang version 23.0.0git (https://github.com/llvm/llvm-project 054e11d1a17e5ba88bb1a8ef32fad3346e80b186)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260325/202603252009.z5G8iyl7-lkp@xxxxxxxxx/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202603252009.z5G8iyl7-lkp@xxxxxxxxx/

All errors (new ones prefixed by >>):

   In file included from arch/s390/kernel/asm-offsets.c:10:
   In file included from include/linux/sched.h:12:
   In file included from arch/s390/include/asm/current.h:13:
   In file included from arch/s390/include/asm/lowcore.h:14:
>> arch/s390/include/asm/ptrace.h:224:9: error: used type 'typeof (regs->psw)' (aka 'const psw_t') where arithmetic or pointer type is required
     224 |         return psw_bits(regs->psw).pstate;
         |                ^~~~~~~~~~~~~~~~~~~
   arch/s390/include/asm/ptrace.h:98:2: note: expanded from macro 'psw_bits'
      98 |         typecheck(psw_t, __psw);                \
         |         ^~~~~~~~~~~~~~~~~~~~~~~
   include/linux/typecheck.h:11:23: note: expanded from macro 'typecheck'
      11 |         typeof(x) __dummy2 = (typeof(x))0; \
         |                              ^          ~
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:98:11: warning: array index 3 is past the end of the array (that has type 'unsigned long[1]') [-Warray-bounds]
      98 |                 return (set->sig[3] | set->sig[2] |
         |                         ^        ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:98:25: warning: array index 2 is past the end of the array (that has type 'unsigned long[1]') [-Warray-bounds]
      98 |                 return (set->sig[3] | set->sig[2] |
         |                                       ^        ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:99:4: warning: array index 1 is past the end of the array (that has type 'unsigned long[1]') [-Warray-bounds]
      99 |                         set->sig[1] | set->sig[0]) == 0;
         |                         ^        ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:101:11: warning: array index 1 is past the end of the array (that has type 'unsigned long[1]') [-Warray-bounds]
     101 |                 return (set->sig[1] | set->sig[0]) == 0;
         |                         ^        ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:114:11: warning: array index 3 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
     114 |                 return  (set1->sig[3] == set2->sig[3]) &&
         |                          ^         ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:114:27: warning: array index 3 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
     114 |                 return  (set1->sig[3] == set2->sig[3]) &&
         |                                          ^         ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:115:5: warning: array index 2 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
     115 |                         (set1->sig[2] == set2->sig[2]) &&
         |                          ^         ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:115:21: warning: array index 2 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
     115 |                         (set1->sig[2] == set2->sig[2]) &&
         |                                          ^         ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:
   In file included from include/linux/ptrace.h:7:
   In file included from include/linux/sched/signal.h:6:
   include/linux/signal.h:116:5: warning: array index 1 is past the end of the array (that has type 'const unsigned long[1]') [-Warray-bounds]
     116 |                         (set1->sig[1] == set2->sig[1]) &&
         |                          ^         ~
   arch/s390/include/asm/signal.h:22:9: note: array 'sig' declared here
      22 |         unsigned long sig[_NSIG_WORDS];
         |         ^
   In file included from arch/s390/kernel/asm-offsets.c:15:
   In file included from arch/s390/include/asm/stacktrace.h:7:


vim +224 arch/s390/include/asm/ptrace.h

952974ac61f686 Heiko Carstens 2010-02-12  221  
afa8fa52a42c31 Jens Remus     2025-12-11  222  static __always_inline bool user_mode(const struct pt_regs *regs)
afa8fa52a42c31 Jens Remus     2025-12-11  223  {
afa8fa52a42c31 Jens Remus     2025-12-11 @224  	return psw_bits(regs->psw).pstate;
afa8fa52a42c31 Jens Remus     2025-12-11  225  }
afa8fa52a42c31 Jens Remus     2025-12-11  226  

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