Re: [PATCH bpf-next 1/2] bpf: Add interval and tnum analysis for signed and unsigned BPF_DIV

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

Hi Yazhou,

kernel test robot noticed the following build warnings:

[auto build test WARNING on bpf-next/master]

url:    https://github.com/intel-lab-lkp/linux/commits/Yazhou-Tang/selftests-bpf-Add-tests-for-BPF_DIV-analysis/20251221-174300
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
patch link:    https://lore.kernel.org/r/tencent_7C98FAECA40C98489ACF4515CE346F031509%40qq.com
patch subject: [PATCH bpf-next 1/2] bpf: Add interval and tnum analysis for signed and unsigned BPF_DIV
config: i386-randconfig-061-20251222 (https://download.01.org/0day-ci/archive/20251223/202512230626.fsj1GsdX-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251223/202512230626.fsj1GsdX-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/202512230626.fsj1GsdX-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> kernel/bpf/tnum.c:16:19: sparse: sparse: symbol 'tnum_bottom' was not declared. Should it be static?
--
   kernel/bpf/verifier.c:23659:38: sparse: sparse: subtraction of functions? Share your drugs
>> kernel/bpf/verifier.c:15184:42: sparse: sparse: unsigned value that used to be signed checked against zero?
   kernel/bpf/verifier.c:15181:24: sparse: signed value source
   kernel/bpf/verifier.c:15191:32: sparse: sparse: unsigned value that used to be signed checked against zero?
   kernel/bpf/verifier.c:15180:24: sparse: signed value source
   kernel/bpf/verifier.c: note: in included file (through include/linux/bpf.h, include/linux/bpf-cgroup.h):
   include/linux/bpfptr.h:65:40: sparse: sparse: cast to non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast from non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast to non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast from non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast to non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast from non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast to non-scalar
   include/linux/bpfptr.h:65:40: sparse: sparse: cast from non-scalar

vim +/tnum_bottom +16 kernel/bpf/tnum.c

    11	
    12	#define TNUM(_v, _m)	(struct tnum){.value = _v, .mask = _m}
    13	/* A completely unknown value */
    14	const struct tnum tnum_unknown = { .value = 0, .mask = -1 };
    15	/* Tnum bottom */
  > 16	const struct tnum tnum_bottom = { .value = -1, .mask = -1 };
    17	

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