Re: [PATCH net v2 1/2] net: phy: Fix formatting specifier to avoid potential string cuts

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

Hi Andy,

kernel test robot noticed the following build errors:

[auto build test ERROR on net/main]

url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/net-phy-Fix-formatting-specifier-to-avoid-potential-string-cuts/20250319-190433
base:   net/main
patch link:    https://lore.kernel.org/r/20250319105813.3102076-2-andriy.shevchenko%40linux.intel.com
patch subject: [PATCH net v2 1/2] net: phy: Fix formatting specifier to avoid potential string cuts
config: loongarch-allyesconfig (https://download.01.org/0day-ci/archive/20250320/202503200024.WkseT3sA-lkp@intel.com/config)
compiler: loongarch64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250320/202503200024.WkseT3sA-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/202503200024.WkseT3sA-lkp@intel.com/

All error/warnings (new ones prefixed by >>):

   In file included from drivers/net/ethernet/broadcom/genet/bcmmii.c:17:
   drivers/net/ethernet/broadcom/genet/bcmmii.c: In function 'bcmgenet_mii_pd_init':
>> include/linux/phy.h:312:20: warning: '%02hhx' directive output may be truncated writing 2 bytes into a region of size between 0 and 60 [-Wformat-truncation=]
     312 | #define PHY_ID_FMT "%s:%02hhx"
         |                    ^~~~~~~~~~~
   drivers/net/ethernet/broadcom/genet/bcmmii.c:604:53: note: in expansion of macro 'PHY_ID_FMT'
     604 |                 snprintf(phy_name, MII_BUS_ID_SIZE, PHY_ID_FMT,
         |                                                     ^~~~~~~~~~
   include/linux/phy.h:312:24: note: format string is defined here
     312 | #define PHY_ID_FMT "%s:%02hhx"
         |                        ^~~~~~
   include/linux/phy.h:312:20: note: using the range [0, 255] for directive argument
     312 | #define PHY_ID_FMT "%s:%02hhx"
         |                    ^~~~~~~~~~~
   drivers/net/ethernet/broadcom/genet/bcmmii.c:604:53: note: in expansion of macro 'PHY_ID_FMT'
     604 |                 snprintf(phy_name, MII_BUS_ID_SIZE, PHY_ID_FMT,
         |                                                     ^~~~~~~~~~
   drivers/net/ethernet/broadcom/genet/bcmmii.c:604:17: note: 'snprintf' output between 4 and 64 bytes into a destination of size 61
     604 |                 snprintf(phy_name, MII_BUS_ID_SIZE, PHY_ID_FMT,
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     605 |                          mdio_bus_id, pd->phy_address);
         |                          ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
--
   loongarch64-linux-ld: arch/loongarch/kernel/head.o: relocation R_LARCH_B26 overflow 0xfffffffff3911f74
   arch/loongarch/kernel/head.o: in function `smpboot_entry':
>> (.ref.text+0x15c): relocation truncated to fit: R_LARCH_B26 against symbol `start_secondary' defined in .text section in arch/loongarch/kernel/smp.o
   loongarch64-linux-ld: final link failed: bad value


vim +312 include/linux/phy.h

   310	
   311	/* Used when trying to connect to a specific phy (mii bus id:phy device id) */
 > 312	#define PHY_ID_FMT "%s:%02hhx"
   313	

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