On Tue, Jan 22, 2019 at 06:38:56PM +0000, Song Liu wrote:
SNIP
> >> in perf_session__process_event, this happens right when processing
> >> buildids in 'perf record', and also in 'perf report', so that is
> >> something badly synthesized that hits perf.data for PERF_RECORD_KSYMBOL.
> >
> > it's reproducible with simple:
> > perf record -e cycles,instructions ls
> >
> > as you said on irc, it's the machine->id_hdr_size size missing
> > there's one more glitch, attached patch fixes that for me
> > you can't use sizeof(struct ksymbol_event), because it includes
> > the name as well.. which screws the size
> >
> > but I don't know that code that much.. might be still something
> > missing
> >
> > jirka
>
> Hi Arnaldo and Jiri,
>
> Thanks for catching and fixing the bug.
>
> I guess the following is OK?
>
> *bpf_event = (struct bpf_event){
> .header = {
> .type = PERF_RECORD_BPF_EVENT,
> .size = sizeof(struct bpf_event),
> },
> .type = PERF_BPF_EVENT_PROG_LOAD,
> .flags = 0,
> .id = info.id,
> };
>
> as struct bpf_event doesn't have variable length name:
>
> struct bpf_event {
> struct perf_event_header header;
> u16 type;
> u16 flags;
> u32 id;
>
> /* for bpf_prog types */
> u8 tag[BPF_TAG_SIZE]; // prog tag
> };
>
> Or we need similar fix?
yep, looks good.. also don't forget to add the 'machine->id_hdr_size'
jirka
