> On Mar 4, 2019, at 5:52 AM, Jiri Olsa <jo...@redhat.com> wrote:
>
> On Wed, Feb 27, 2019 at 09:06:35PM -0800, Song Liu wrote:
>
> SNIP
>
>> +static int process_bpf_prog_info(struct feat_fd *ff,
>> + void *data __maybe_unused)
>> +{
>> + struct bpf_prog_info_linear *info_linear;
>> + struct bpf_prog_info_node *info_node;
>> + struct perf_env *env = &ff->ph->env;
>> + u32 count, i;
>> + int err = -1;
>> +
>> + if (do_read_u32(ff, &count))
>> + return -1;
>> +
>> + down_write(&env->bpf_progs.lock);
>> +
>> + for (i = 0; i < count; ++i) {
>> + u32 info_len, data_len;
>> +
>> + info_linear = NULL;
>> + info_node = NULL;
>> + if (do_read_u32(ff, &info_len))
>> + goto out;
>> + if (do_read_u32(ff, &data_len))
>> + goto out;
>> +
>> + 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 */
>> + if (ff->ph->needs_swap) {
>> + free(info_linear);
>> + continue;
>> + }
>
> so in this case we can check for needs_swap in the begining
> of the function and bail out without reading all the data
If we bail out, perf-record will fail. If we read all the data
but ignore them, perf-record will continue without bpf annotation
support. I think the latter is a better experience with little
effort here.
>
> also please display soem error message saying we don't support
> ebpf progs data report over the different endianity
I will add a warning in the next version.
Thanks,
Song
