On Tue, Jan 22, 2019 at 07:24:43PM +0000, Song Liu wrote:
>
>
> > On Jan 22, 2019, at 11:15 AM, Jiri Olsa <jo...@redhat.com> wrote:
> >
> > 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
>
> So we still need something like?
>
> diff --git i/tools/perf/util/bpf-event.c w/tools/perf/util/bpf-event.c
> index 01e1dc1bb7fb..d7bf45485820 100644
> --- i/tools/perf/util/bpf-event.c
> +++ w/tools/perf/util/bpf-event.c
> @@ -4,6 +4,7 @@
> #include <bpf/bpf.h>
> #include <bpf/btf.h>
> #include <linux/btf.h>
> +#include "machine.h"
> #include "bpf-event.h"
> #include "debug.h"
> #include "symbol.h"
> @@ -187,7 +188,7 @@ static int perf_event__synthesize_one_bpf_prog(struct
> perf_tool *tool,
> *bpf_event = (struct bpf_event){
> .header = {
> .type = PERF_RECORD_BPF_EVENT,
> - .size = sizeof(struct bpf_event),
> + .size = sizeof(struct bpf_event) +
> machine->id_hdr_size,
> },
> .type = PERF_BPF_EVENT_PROG_LOAD,
> .flags = 0,
>
> Would you send the official patch? Or would you prefer me sending it?
plese send it, thanks
jirka
