Re: [PATCH v2 next 2/4] lib: mul_u64_u64_div_u64() Use BUG_ON() for divide by zero

Re: [PATCH v2 next 2/4] lib: mul_u64_u64_div_u64() Use BUG_ON() for divide by zero

[kernel test robot]

Hi David,

kernel test robot noticed the following build errors:

[auto build test ERROR on next-20250516]

url:    https://github.com/intel-lab-lkp/linux/commits/David-Laight/lib-mul_u64_u64_div_u64-rename-parameter-c-to-d/20250518-214037
base:   next-20250516
patch link:    https://lore.kernel.org/r/20250518133848.5811-3-david.laight.linux%40gmail.com
patch subject: [PATCH v2 next 2/4] lib: mul_u64_u64_div_u64() Use BUG_ON() for divide by zero
config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20250518/202505182351.bPFZE1vO-lkp@intel.com/config)
compiler: or1k-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250518/202505182351.bPFZE1vO-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/202505182351.bPFZE1vO-lkp@intel.com/

All errors (new ones prefixed by >>):

   lib/math/div64.c: In function 'mul_u64_u64_div_u64':
>> lib/math/div64.c:190:9: error: implicit declaration of function 'BUG_ON' [-Wimplicit-function-declaration]
     190 |         BUG_ON(!d);
         |         ^~~~~~


vim +/BUG_ON +190 lib/math/div64.c

   185	
   186	#ifndef mul_u64_u64_div_u64
   187	u64 mul_u64_u64_div_u64(u64 a, u64 b, u64 d)
   188	{
   189		/* Trigger exception if divisor is zero */
 > 190		BUG_ON(!d);
   191	
   192		if (ilog2(a) + ilog2(b) <= 62)
   193			return div64_u64(a * b, d);
   194	

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

Re: [PATCH v2 next 2/4] lib: mul_u64_u64_div_u64() Use BUG_ON() for divide by zero

[David Laight]

On Sun, 18 May 2025 23:42:44 +0800
kernel test robot <lkp@intel.com> wrote:

> Hi David,
> 
> kernel test robot noticed the following build errors:
> 
> [auto build test ERROR on next-20250516]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/David-Laight/lib-mul_u64_u64_div_u64-rename-parameter-c-to-d/20250518-214037
> base:   next-20250516
> patch link:    https://lore.kernel.org/r/20250518133848.5811-3-david.laight.linux%40gmail.com
> patch subject: [PATCH v2 next 2/4] lib: mul_u64_u64_div_u64() Use BUG_ON() for divide by zero
> config: openrisc-allnoconfig (https://download.01.org/0day-ci/archive/20250518/202505182351.bPFZE1vO-lkp@intel.com/config)
> compiler: or1k-linux-gcc (GCC) 14.2.0
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250518/202505182351.bPFZE1vO-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/202505182351.bPFZE1vO-lkp@intel.com/
> 
> All errors (new ones prefixed by >>):
> 
>    lib/math/div64.c: In function 'mul_u64_u64_div_u64':
> >> lib/math/div64.c:190:9: error: implicit declaration of function 'BUG_ON' [-Wimplicit-function-declaration]  
>      190 |         BUG_ON(!d);
>          |         ^~~~~~

compiles fine on x86 :-(