Messages in this thread | | | From | Song Liu <> | Subject | Re: [PATCH v5 perf,bpf 07/15] perf, bpf: save bpf_prog_info information as headers to perf.data | Date | Mon, 4 Mar 2019 19:36:14 +0000 |
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> On Mar 4, 2019, at 5:52 AM, Jiri Olsa <jolsa@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
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