On Thu, Aug 24, 2017 at 06:27:30PM +0200, Jiri Olsa wrote: > Adding leader's state check into perf_output_read_group > to ensure we read only leader, which is scheduled in. > > Similar check is already there for siblings. > > Signed-off-by: Jiri Olsa <[email protected]> > --- > kernel/events/core.c | 10 +++++++--- > 1 file changed, 7 insertions(+), 3 deletions(-) > > diff --git a/kernel/events/core.c b/kernel/events/core.c > index 30e30e94ea32..9a2791afe051 100644 > --- a/kernel/events/core.c > +++ b/kernel/events/core.c > @@ -5760,6 +5760,11 @@ void perf_event__output_id_sample(struct perf_event > *event, > __perf_event__output_id_sample(handle, sample); > } > > +static bool can_read(struct perf_event *event) > +{ > + return event->state == PERF_EVENT_STATE_ACTIVE; > +} > + > static void perf_output_read_one(struct perf_output_handle *handle, > struct perf_event *event, > u64 enabled, u64 running) > @@ -5800,7 +5805,7 @@ static void perf_output_read_group(struct > perf_output_handle *handle, > if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) > values[n++] = running; > > - if (leader != event) > + if ((leader != event) && can_read(leader)) > leader->pmu->read(leader); > > values[n++] = perf_event_count(leader); > @@ -5812,8 +5817,7 @@ static void perf_output_read_group(struct > perf_output_handle *handle, > list_for_each_entry(sub, &leader->sibling_list, group_entry) { > n = 0; > > - if ((sub != event) && > - (sub->state == PERF_EVENT_STATE_ACTIVE)) > + if ((sub != event) && can_read(sub)) > sub->pmu->read(sub); > > values[n++] = perf_event_count(sub);
I'm not seeing how this makes sense. Groups should either _all_ be scheduled or not at all. Please explain.
