netdev - Re: [PATCH bpf] bpf: Only print ref_obj

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Date:   Mon, 18 Mar 2019 12:26:23 -0700
From:   Andrii Nakryiko <andrii.nakryiko@...il.com>
To:     Martin KaFai Lau <kafai@...com>
Cc:     bpf@...r.kernel.org, Networking <netdev@...r.kernel.org>,
        Alexei Starovoitov <ast@...com>,
        Daniel Borkmann <daniel@...earbox.net>,
        Kernel Team <kernel-team@...com>,
        Naresh Kamboju <naresh.kamboju@...aro.org>
Subject: Re: [PATCH bpf] bpf: Only print ref_obj_id for refcounted reg

On Mon, Mar 18, 2019 at 10:37 AM Martin KaFai Lau <kafai@...com> wrote:
>
> Naresh reported that test_align fails because of the mismatch at the
> verbose printout of the register states.  The reason is due to the newly
> added ref_obj_id.
>
> ref_obj_id is only useful for refcounted reg.  Thus, this patch fixes it
> by only printing ref_obj_id for refcounted reg.  While at it, it also uses
> comma instead of space to separate between "id" and "ref_obj_id".
>
> Fixes: 1b986589680a ("bpf: Fix bpf_tcp_sock and bpf_sk_fullsock issue related to bpf_sk_release")
> Reported-by: Naresh Kamboju <naresh.kamboju@...aro.org>
> Signed-off-by: Martin KaFai Lau <kafai@...com>
> ---
>  kernel/bpf/verifier.c | 13 +++++++++++--
>  1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
> index 86f9cd5d1c4e..5aa810882583 100644
> --- a/kernel/bpf/verifier.c
> +++ b/kernel/bpf/verifier.c
> @@ -352,6 +352,14 @@ static bool reg_may_point_to_spin_lock(const struct bpf_reg_state *reg)
>                 map_value_has_spin_lock(reg->map_ptr);
>  }
>
> +static bool reg_type_may_be_refcounted_or_null(enum bpf_reg_type type)
> +{
> +       return type == PTR_TO_SOCKET ||
> +               type == PTR_TO_SOCKET_OR_NULL ||
> +               type == PTR_TO_TCP_SOCK ||
> +               type == PTR_TO_TCP_SOCK_OR_NULL;
> +}
> +
>  static bool arg_type_may_be_refcounted(enum bpf_arg_type type)
>  {
>         return type == ARG_PTR_TO_SOCK_COMMON;
> @@ -451,8 +459,9 @@ static void print_verifier_state(struct bpf_verifier_env *env,
>                         if (t == PTR_TO_STACK)
>                                 verbose(env, ",call_%d", func(env, reg)->callsite);
>                 } else {
> -                       verbose(env, "(id=%d ref_obj_id=%d", reg->id,
> -                               reg->ref_obj_id);
> +                       verbose(env, "(id=%d", reg->id);
> +                       if (reg_type_may_be_refcounted_or_null(t))
> +                               verbose(env, ",ref_obj_id=%d", reg->ref_obj_id);
>                         if (t != SCALAR_VALUE)
>                                 verbose(env, ",off=%d", reg->off);
>                         if (type_is_pkt_pointer(t))
> --
> 2.17.1
>

lgtm

Acked-by: Andrii Nakryiko <andriin@...com>