On Wed, Dec 22, 2021 at 5:10 AM Jackie Liu <liu.yun@xxxxxxxxx> wrote:
>
> From: Jackie Liu <liuyun01@xxxxxxxxxx>
>
> s32 is always true regardless of the values of its operands. let's
> cleanup.
>
> Fixes: e572ff80f05c ("bpf: Make 32->64 bounds propagation slightly more robust")
> Reported-by: k2ci <kernel-bot@xxxxxxxxxx>
> Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx>
> ---
> kernel/bpf/verifier.c | 8 +-------
> 1 file changed, 1 insertion(+), 7 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index b532f1058d35..43812ee58304 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -1366,11 +1366,6 @@ static void __reg_bound_offset(struct bpf_reg_state *reg)
> reg->var_off = tnum_or(tnum_clear_subreg(var64_off), var32_off);
> }
>
> -static bool __reg32_bound_s64(s32 a)
> -{
> - return a >= 0 && a <= S32_MAX;
> -}
> -
The code is the best documentation.
Here it clearly describes the intent.
Please ignore compiler warnings.
