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

From: Andy Shevchenko
Date: Wed Mar 19 2025 - 11:52:31 EST


On Wed, Mar 19, 2025 at 11:37:19PM +0800, kernel test robot wrote:
> Hi Andy,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING 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: x86_64-allmodconfig (https://download.01.org/0day-ci/archive/20250319/202503192340.iVN44lM2-lkp@xxxxxxxxx/config)
> compiler: clang version 20.1.0 (https://github.com/llvm/llvm-project 24a30daaa559829ad079f2ff7f73eb4e18095f88)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250319/202503192340.iVN44lM2-lkp@xxxxxxxxx/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@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202503192340.iVN44lM2-lkp@xxxxxxxxx/
>
> All warnings (new ones prefixed by >>):
>
> >> drivers/net/usb/ax88172a.c:312:20: warning: format specifies type 'unsigned char' but the argument has type 'u16' (aka 'unsigned short') [-Wformat]
> 311 | snprintf(priv->phy_name, 20, PHY_ID_FMT,
> | ~~~~~~~~~~
> 312 | priv->mdio->id, priv->phy_addr);
> | ^~~~~~~~~~~~~~
> 1 warning generated.

It's fun: while working around GCC complain, clang does not agree with... :-)
Let's wait more, probably the simplest fix (if this becomes only a single user
of the non-byte parameter) is to move it to u8.

--
With Best Regards,
Andy Shevchenko