Re: [PATCH 1/2] sched: Defend cfs and rt bandwidth quota against overflow

[kbuild test robot]

Hi Huaixin,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tip/sched/core]
[also build test WARNING on tip/auto-latest linus/master linux/master v5.7-rc2 next-20200421]
[if your patch is applied to the wrong git tree, please drop us a note to help
improve the system. BTW, we also suggest to use '--base' option to specify the
base tree in git format-patch, please see https://stackoverflow.com/a/37406982]

url:    https://github.com/0day-ci/linux/commits/Huaixin-Chang/Two-small-fixes-for-bandwidth-controller/20200421-230027
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git 8f3d9f354286745c751374f5f1fcafee6b3f3136
config: sh-allmodconfig (attached as .config)
compiler: sh4-linux-gcc (GCC) 9.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day GCC_VERSION=9.3.0 make.cross ARCH=sh 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kbuild test robot <lkp@xxxxxxxxx>

All warnings (new ones prefixed by >>):

   In file included from kernel/sched/core.c:9:
>> kernel/sched/sched.h:1922:28: warning: left shift count >= width of type [-Wshift-count-overflow]
    1922 | #define MAX_BW_USEC  ((1UL << MAX_BW_BITS) - 1)
         |                            ^~
>> kernel/sched/core.c:7394:36: note: in expansion of macro 'MAX_BW_USEC'
    7394 | static const u64 max_cfs_runtime = MAX_BW_USEC * NSEC_PER_USEC;
         |                                    ^~~~~~~~~~~
--
   In file included from kernel/sched/rt.c:6:
>> kernel/sched/sched.h:1922:28: warning: left shift count >= width of type [-Wshift-count-overflow]
    1922 | #define MAX_BW_USEC  ((1UL << MAX_BW_BITS) - 1)
         |                            ^~
>> kernel/sched/rt.c:2573:35: note: in expansion of macro 'MAX_BW_USEC'
    2573 | static const u64 max_rt_runtime = MAX_BW_USEC * NSEC_PER_USEC;
         |                                   ^~~~~~~~~~~

vim +1922 kernel/sched/sched.h

  1917	
  1918	#define BW_SHIFT		20
  1919	#define BW_UNIT			(1 << BW_SHIFT)
  1920	#define RATIO_SHIFT		8
  1921	#define MAX_BW_BITS		(64 - BW_SHIFT)
> 1922	#define MAX_BW_USEC		((1UL << MAX_BW_BITS) - 1)
  1923	unsigned long to_ratio(u64 period, u64 runtime);
  1924	

---
0-DAY CI Kernel Test Service, Intel Corporation
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Attachment: .config.gz
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