linux-kernel - kernel/bpf/verifier.c:1371 __reg32_bound_s64() warn: always true condition '(a <= (((~0) >> 1))) => (s32min-s32max <= s32max)'

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Date:   Thu, 23 Dec 2021 02:10:31 +0800
From:   kernel test robot <lkp@...el.com>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     kbuild-all@...ts.01.org, linux-kernel@...r.kernel.org,
        John Fastabend <john.fastabend@...il.com>
Subject: kernel/bpf/verifier.c:1371 __reg32_bound_s64() warn: always true
 condition '(a <= (((~0) >> 1))) => (s32min-s32max <= s32max)'

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   2f47a9a4dfa3674fad19a49b40c5103a9a8e1589
commit: e572ff80f05c33cd0cb4860f864f5c9c044280b6 bpf: Make 32->64 bounds propagation slightly more robust
date:   6 days ago
config: x86_64-randconfig-m001-20211222 (https://download.01.org/0day-ci/archive/20211223/202112230216.VClmulwe-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>

smatch warnings:
kernel/bpf/verifier.c:1371 __reg32_bound_s64() warn: always true condition '(a <= (((~0) >> 1))) => (s32min-s32max <= s32max)'

vim +1371 kernel/bpf/verifier.c

  1368	
  1369	static bool __reg32_bound_s64(s32 a)
  1370	{
> 1371		return a >= 0 && a <= S32_MAX;
  1372	}
  1373	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org