[PATCH] riscv: kgdb: Prefer strscpy instead of strcpy

[Miquel Sabaté Solà]

Hello,

kernel test robot @ 2025-09-16 17:10 +08:

> Hi Miquel,
>
> kernel test robot noticed the following build errors:
>
> [auto build test ERROR on linus/master]
> [also build test ERROR on v6.17-rc6 next-20250915]
> [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/Miquel-Sabat-Sol/riscv-kgdb-Prefer-strscpy-instead-of-strcpy/20250916-040750
> base:   linus/master
> patch link:    https://lore.kernel.org/r/20250915200644.200498-1-mikisabate%40gmail.com
> patch subject: [PATCH] riscv: kgdb: Prefer strscpy instead of strcpy
> config: riscv-randconfig-002-20250916 (https://download.01.org/0day-ci/archive/20250916/202509161619.eJeLbfU0-lkp@intel.com/config)
> compiler: riscv32-linux-gcc (GCC) 10.5.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250916/202509161619.eJeLbfU0-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 at intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202509161619.eJeLbfU0-lkp@intel.com/
>
> All errors (new ones prefixed by >>):
>
>    In file included from include/linux/ptrace.h:5,
>                     from arch/riscv/kernel/kgdb.c:6:
>    arch/riscv/kernel/kgdb.c: In function 'kgdb_arch_handle_qxfer_pkt':
>>> include/linux/compiler.h:197:67: error: static assertion failed: "must be array"
>      197 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
>          |                                                                   ^~~~~~~~~~~~~~
>    include/linux/compiler.h:202:28: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
>      202 | #define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(!__is_array(a), \
>          |                            ^~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/string.h:80:40: note: in expansion of macro '__must_be_array'
>       80 |  sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst) + \
>          |                                        ^~~~~~~~~~~~~~~
>    include/linux/args.h:25:24: note: in expansion of macro '__strscpy0'
>       25 | #define __CONCAT(a, b) a ## b
>          |                        ^
>    include/linux/args.h:26:27: note: in expansion of macro '__CONCAT'
>       26 | #define CONCATENATE(a, b) __CONCAT(a, b)
>          |                           ^~~~~~~~
>    include/linux/string.h:114:2: note: in expansion of macro 'CONCATENATE'
>      114 |  CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
>          |  ^~~~~~~~~~~
>    arch/riscv/kernel/kgdb.c:268:3: note: in expansion of macro 'strscpy'
>      268 |   strscpy(remcom_out_buffer, riscv_gdb_stub_target_desc);
>          |   ^~~~~~~
>>> include/linux/compiler.h:197:67: error: static assertion failed: "must be array"
>      197 | #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
>          |                                                                   ^~~~~~~~~~~~~~
>    include/linux/compiler.h:202:28: note: in expansion of macro '__BUILD_BUG_ON_ZERO_MSG'
>      202 | #define __must_be_array(a) __BUILD_BUG_ON_ZERO_MSG(!__is_array(a), \
>          |                            ^~~~~~~~~~~~~~~~~~~~~~~
>    include/linux/string.h:80:40: note: in expansion of macro '__must_be_array'
>       80 |  sized_strscpy(dst, src, sizeof(dst) + __must_be_array(dst) + \
>          |                                        ^~~~~~~~~~~~~~~
>    include/linux/args.h:25:24: note: in expansion of macro '__strscpy0'
>       25 | #define __CONCAT(a, b) a ## b
>          |                        ^
>    include/linux/args.h:26:27: note: in expansion of macro '__CONCAT'
>       26 | #define CONCATENATE(a, b) __CONCAT(a, b)
>          |                           ^~~~~~~~
>    include/linux/string.h:114:2: note: in expansion of macro 'CONCATENATE'
>      114 |  CONCATENATE(__strscpy, COUNT_ARGS(__VA_ARGS__))(dst, src, __VA_ARGS__)
>          |  ^~~~~~~~~~~
>    arch/riscv/kernel/kgdb.c:271:3: note: in expansion of macro 'strscpy'
>      271 |   strscpy(remcom_out_buffer, riscv_gdb_stub_cpuxml);
>          |   ^~~~~~~
>
>
> vim +197 include/linux/compiler.h
>
> 230fa253df6352 Christian Borntraeger 2014-11-25  193
> cb7380de9e4cbc Kees Cook             2025-02-05  194  #ifdef __CHECKER__
> 243c90e917f5cf Vincent Mailhol       2025-03-29  195  #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) (0)
> cb7380de9e4cbc Kees Cook             2025-02-05  196  #else /* __CHECKER__ */
> 243c90e917f5cf Vincent Mailhol       2025-03-29 @197  #define __BUILD_BUG_ON_ZERO_MSG(e, msg, ...) ((int)sizeof(struct {_Static_assert(!(e), msg);}))
> cb7380de9e4cbc Kees Cook             2025-02-05  198  #endif /* __CHECKER__ */
> cb7380de9e4cbc Kees Cook             2025-02-05  199

I was testing on the RISC-V tree, but I should've definitely tested this
on 'next' instead to catch this compiler error.

Since this is not too important, feel free to drop this patch.

Sorry for the noise,
Miquel
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