Re: [PATCH 5/6] ptrace: introduce PTRACE_SET_SYSCALL_INFO request

[kernel test robot <lkp@intel.com>]

Hi Dmitry,

kernel test robot noticed the following build errors:

[auto build test ERROR on openrisc/for-next]
[also build test ERROR on powerpc/next powerpc/fixes s390/features uml/next jcmvbkbc-xtensa/xtensa-for-next arnd-asm-generic/master vgupta-arc/for-curr arm64/for-next/core linus/master uml/fixes tip/x86/core vgupta-arc/for-next v6.13-rc6 next-20250108]
[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/Dmitry-V-Levin/Revert-arch-remove-unused-function-syscall_set_arguments/20250108-070658
base:   https://github.com/openrisc/linux.git for-next
patch link:    https://lore.kernel.org/r/20250107230456.GE30633%40strace.io
patch subject: [PATCH 5/6] ptrace: introduce PTRACE_SET_SYSCALL_INFO request
config: hexagon-allnoconfig (https://download.01.org/0day-ci/archive/20250109/202501090919.TiLTOhaq-lkp@intel.com/config)
compiler: clang version 20.0.0git (https://github.com/llvm/llvm-project 096551537b2a747a3387726ca618ceeb3950e9bc)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250109/202501090919.TiLTOhaq-lkp@intel.com/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@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501090919.TiLTOhaq-lkp@intel.com/

All errors (new ones prefixed by >>):

>> kernel/ptrace.c:1053:3: error: call to undeclared function 'syscall_set_return_value'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1053 |                 syscall_set_return_value(child, regs, -ENOSYS, 0);
         |                 ^
   kernel/ptrace.c:1053:3: note: did you mean 'syscall_get_return_value'?
   arch/hexagon/include/asm/syscall.h:56:20: note: 'syscall_get_return_value' declared here
      56 | static inline long syscall_get_return_value(struct task_struct *task,
         |                    ^
   kernel/ptrace.c:1075:3: error: call to undeclared function 'syscall_set_return_value'; ISO C99 and later do not support implicit function declarations [-Wimplicit-function-declaration]
    1075 |                 syscall_set_return_value(child, regs, info->exit.rval, 0);
         |                 ^
   2 errors generated.


vim +/syscall_set_return_value +1053 kernel/ptrace.c

  1021	
  1022	static unsigned long
  1023	ptrace_set_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
  1024				      struct ptrace_syscall_info *info)
  1025	{
  1026		unsigned long args[ARRAY_SIZE(info->entry.args)];
  1027		int nr = info->entry.nr;
  1028		int i;
  1029	
  1030		if (nr != info->entry.nr)
  1031			return -ERANGE;
  1032	
  1033		for (i = 0; i < ARRAY_SIZE(args); i++) {
  1034			args[i] = info->entry.args[i];
  1035			if (args[i] != info->entry.args[i])
  1036				return -ERANGE;
  1037		}
  1038	
  1039		syscall_set_nr(child, regs, nr);
  1040		syscall_set_arguments(child, regs, args);
  1041		if (nr == -1) {
  1042			/*
  1043			 * When the syscall number is set to -1, the syscall will be
  1044			 * skipped.  In this case also set the syscall return value to
  1045			 * -ENOSYS, otherwise on some architectures the corresponding
  1046			 * struct pt_regs field will remain unchanged.
  1047			 *
  1048			 * Note that on some architectures syscall_set_return_value()
  1049			 * modifies one of the struct pt_regs fields also modified by
  1050			 * syscall_set_arguments(), so the former should be called
  1051			 * after the latter.
  1052			 */
> 1053			syscall_set_return_value(child, regs, -ENOSYS, 0);
  1054		}
  1055	
  1056		return 0;
  1057	}
  1058	

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