Re: [PATCH v4 perf,bpf 07/15] perf, bpf: save bpf_prog_info information as headers to perf.data

[Jiri Olsa]

On Mon, Feb 25, 2019 at 04:20:11PM -0800, Song Liu wrote:

SNIP

> +             if (info_len > sizeof(struct bpf_prog_info)) {
> +                     pr_warning("detected invalid bpf_prog_info\n");
> +                     goto out;
> +             }
> +
> +             info_linear = malloc(sizeof(struct bpf_prog_info_linear) +
> +                                  data_len);
> +             if (!info_linear)
> +                     goto out;
> +             info_linear->info_len = sizeof(struct bpf_prog_info);
> +             info_linear->data_len = data_len;
> +             if (do_read_u64(ff, (u64 *)(&info_linear->arrays)))
> +                     goto out;
> +             if (__do_read(ff, &info_linear->info, info_len))
> +                     goto out;
> +             if (info_len < sizeof(struct bpf_prog_info))
> +                     memset(((void *)(&info_linear->info)) + info_len, 0,
> +                            sizeof(struct bpf_prog_info) - info_len);
> +
> +             if (__do_read(ff, info_linear->data, data_len))
> +                     goto out;
> +
> +             /* endian mismatch, drop the info, continue */

so there's no way we can swap the data? why?

jirka

> +             if (ff->ph->needs_swap) {
> +                     free(info_linear);
> +                     continue;
> +             }

SNIP