Re: [PATCH net-next 7/7] net/mlx5e: Use extack in set rxfh callback

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

Hi Tariq,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 312e6f7676e63bbb9b81e5c68e580a9f776cc6f0]

url:    https://github.com/intel-lab-lkp/linux/commits/Tariq-Toukan/net-mlx5-HWS-Generalize-complex-matchers/20250922-170716
base:   312e6f7676e63bbb9b81e5c68e580a9f776cc6f0
patch link:    https://lore.kernel.org/r/1758531671-819655-8-git-send-email-tariqt%40nvidia.com
patch subject: [PATCH net-next 7/7] net/mlx5e: Use extack in set rxfh callback
config: x86_64-rhel-9.4-rust (https://download.01.org/0day-ci/archive/20250923/202509231125.Tsan9Qny-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
rustc: rustc 1.88.0 (6b00bc388 2025-06-23)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250923/202509231125.Tsan9Qny-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/202509231125.Tsan9Qny-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c:1508:4: warning: 'snprintf' will always be truncated; specified size is 80, but format string expands to at least 131 [-Wformat-truncation]
    1508 |                         NL_SET_ERR_MSG_FMT_MOD(
         |                         ^
   include/linux/netlink.h:131:2: note: expanded from macro 'NL_SET_ERR_MSG_FMT_MOD'
     131 |         NL_SET_ERR_MSG_FMT((extack), KBUILD_MODNAME ": " fmt, ##args)
         |         ^
   include/linux/netlink.h:116:6: note: expanded from macro 'NL_SET_ERR_MSG_FMT'
     116 |         if (snprintf(__extack->_msg_buf, NETLINK_MAX_FMTMSG_LEN,               \
         |             ^
   1 warning generated.


vim +/snprintf +1508 drivers/net/ethernet/mellanox/mlx5/core/en_ethtool.c

  1495	
  1496	static int mlx5e_rxfh_hfunc_check(struct mlx5e_priv *priv,
  1497					  const struct ethtool_rxfh_param *rxfh,
  1498					  struct netlink_ext_ack *extack)
  1499	{
  1500		unsigned int count;
  1501	
  1502		count = priv->channels.params.num_channels;
  1503	
  1504		if (rxfh->hfunc == ETH_RSS_HASH_XOR) {
  1505			unsigned int xor8_max_channels = mlx5e_rqt_max_num_channels_allowed_for_xor8();
  1506	
  1507			if (count > xor8_max_channels) {
> 1508				NL_SET_ERR_MSG_FMT_MOD(
  1509					extack,
  1510					"Cannot set RSS hash function to XOR, current number of channels (%d) exceeds the maximum allowed for XOR8 RSS hfunc (%d)\n",
  1511					count, xor8_max_channels);
  1512				return -EINVAL;
  1513			}
  1514		}
  1515	
  1516		return 0;
  1517	}
  1518	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki