Re: [PATCH] x86: string_32.h: Provide basic sanity checks for fallback memcpy()

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

Hi Kees,

kernel test robot noticed the following build errors:

[auto build test ERROR on tip/master]
[also build test ERROR on tip/x86/core kees/for-next/pstore kees/for-next/kspp linus/master v6.15-rc7 next-20250523]
[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/Kees-Cook/x86-string_32-h-Provide-basic-sanity-checks-for-fallback-memcpy/20250523-122803
base:   tip/master
patch link:    https://lore.kernel.org/r/20250523042635.work.579-kees%40kernel.org
patch subject: [PATCH] x86: string_32.h: Provide basic sanity checks for fallback memcpy()
config: i386-buildonly-randconfig-004-20250524 (https://download.01.org/0day-ci/archive/20250524/202505240850.vTrqyqJx-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250524/202505240850.vTrqyqJx-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/202505240850.vTrqyqJx-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/x86/crypto/serpent_sse2_glue.c: In function 'serpent_decrypt_cbc_xway':
>> arch/x86/crypto/serpent_sse2_glue.c:39:19: error: assignment to 'const u8 *' {aka 'const unsigned char *'} from incompatible pointer type 'u8 (*)[16]' {aka 'unsigned char (*)[16]'} [-Werror=incompatible-pointer-types]
      39 |                 s = memcpy(buf, src, sizeof(buf));
         |                   ^
   cc1: some warnings being treated as errors


vim +39 arch/x86/crypto/serpent_sse2_glue.c

e0f409dcb82e463 Eric Biggers    2018-02-19  32  
9ad58b46f814edd Ard Biesheuvel  2021-01-05  33  static void serpent_decrypt_cbc_xway(const void *ctx, u8 *dst, const u8 *src)
e81792fbc2a6fa4 Jussi Kivilinna 2012-06-18  34  {
9ad58b46f814edd Ard Biesheuvel  2021-01-05  35  	u8 buf[SERPENT_PARALLEL_BLOCKS - 1][SERPENT_BLOCK_SIZE];
9ad58b46f814edd Ard Biesheuvel  2021-01-05  36  	const u8 *s = src;
e81792fbc2a6fa4 Jussi Kivilinna 2012-06-18  37  
9ad58b46f814edd Ard Biesheuvel  2021-01-05  38  	if (dst == src)
9ad58b46f814edd Ard Biesheuvel  2021-01-05 @39  		s = memcpy(buf, src, sizeof(buf));
9ad58b46f814edd Ard Biesheuvel  2021-01-05  40  	serpent_dec_blk_xway(ctx, dst, src);
9ad58b46f814edd Ard Biesheuvel  2021-01-05  41  	crypto_xor(dst + SERPENT_BLOCK_SIZE, s, sizeof(buf));
e81792fbc2a6fa4 Jussi Kivilinna 2012-06-18  42  }
e81792fbc2a6fa4 Jussi Kivilinna 2012-06-18  43  

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