Re: [PATCH bpf-next] bpf: Fix a typo in comment for DFS algorithm

[Alexei Starovoitov]

On Tue, Oct 25, 2022 at 7:42 PM Xu Kuohai <xukuohai@xxxxxxxxxxxxxxx> wrote:
>
> From: Xu Kuohai <xukuohai@xxxxxxxxxx>
>
> There is a typo in comment for DFS algorithm in bpf/verifier.c. The top
> element should not be popped until all its neighbors have been checked.
> Fix it.
>
> Fixes: 475fb78fbf48 ("bpf: verifier (add branch/goto checks)")
> Signed-off-by: Xu Kuohai <xukuohai@xxxxxxxxxx>
> ---
>  kernel/bpf/verifier.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index b83a8d420520..96ba5ea6d1a6 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -10662,7 +10662,7 @@ static int check_return_code(struct bpf_verifier_env *env)
>   * 3      let S be a stack
>   * 4      S.push(v)
>   * 5      while S is not empty
> - * 6            t <- S.pop()
> + * 6            t <- S.top()

Even with this fix the comment is not quite accurate.
I wonder whether we should keep it or delete it completely.
At least please use 'peek' instead of 'top'.