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charset="utf-8" When 'perf sched latency' is executed on a perf.data file that lacks tracepoint samples (i.e., a file recorded without the -R flag or containing only non-tracepoint events), perf_session__has_traces() correctly outputs an error message. However, perf_sched__read_events() subsequently falls through and returns 0 (success). Consequently, caller functions such as perf_sched__lat() assume event processing succeeded and proceed to render empty latency header tables and total summary statistics. Fix this behaviour by ensuring perf_sched__read_events() aborts early and returns a suitable error code when perf_session__has_traces() evaluates to false. This prevents superfluous table output from being generated when no trace data is available. Fixes: 27295592c22e ("perf session: Share the common trace sample_check rou= tine as perf_session__has_traces") Signed-off-by: Aaron Tomlin --- tools/perf/builtin-sched.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c index 7fd63a9db457..b3cf678573e0 100644 --- a/tools/perf/builtin-sched.c +++ b/tools/perf/builtin-sched.c @@ -2001,7 +2001,7 @@ static int perf_sched__read_events(struct perf_sched = *sched) .mode =3D PERF_DATA_MODE_READ, .force =3D sched->force, }; - int rc =3D -1; + int rc =3D -1, err; =20 session =3D perf_session__new(&data, &sched->tool); if (IS_ERR(session)) { @@ -2018,18 +2018,19 @@ static int perf_sched__read_events(struct perf_sche= d *sched) if (perf_session__set_tracepoints_handlers(session, handlers)) goto out_delete; =20 - if (perf_session__has_traces(session, "record -R")) { - int err =3D perf_session__process_events(session); - if (err) { - pr_err("Failed to process events, error %d", err); - goto out_delete; - } + if (!perf_session__has_traces(session, "record -R")) + goto out_delete; =20 - sched->nr_events =3D session->evlist->stats.nr_events[0]; - sched->nr_lost_events =3D session->evlist->stats.total_lost; - sched->nr_lost_chunks =3D session->evlist->stats.nr_events[PERF_RECORD_L= OST]; + err =3D perf_session__process_events(session); + if (err) { + pr_err("Failed to process events, error %d", err); + goto out_delete; } =20 + sched->nr_events =3D session->evlist->stats.nr_events[0]; + sched->nr_lost_events =3D session->evlist->stats.total_lost; + sched->nr_lost_chunks =3D session->evlist->stats.nr_events[PERF_RECORD_LO= ST]; + rc =3D 0; out_delete: perf_session__delete(session); --=20 2.54.0