Returning NULL will cause the python interpreter to fail but not
report an error. If none wants to be returned then Py_None needs
returning. Set the error for the cases returning NULL so that more
meaningful interpreter behavior is had.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/python.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 2f28f71325a8..3affde0ad15a 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -475,13 +475,19 @@ static PyObject *pyrf_event__new(const union perf_event *event)
 	if ((event->header.type < PERF_RECORD_MMAP ||
 	     event->header.type > PERF_RECORD_SAMPLE) &&
 	    !(event->header.type == PERF_RECORD_SWITCH ||
-	      event->header.type == PERF_RECORD_SWITCH_CPU_WIDE))
+	      event->header.type == PERF_RECORD_SWITCH_CPU_WIDE)) {
+		PyErr_Format(PyExc_TypeError, "Unexpected header type %u",
+			     event->header.type);
 		return NULL;
+	}
 
 	// FIXME this better be dynamic or we need to parse everything
 	// before calling perf_mmap__consume(), including tracepoint fields.
-	if (sizeof(pevent->event) < event->header.size)
+	if (sizeof(pevent->event) < event->header.size) {
+		PyErr_Format(PyExc_TypeError, "Unexpected event size: %zd < %u",
+			     sizeof(pevent->event), event->header.size);
 		return NULL;
+	}
 
 	ptype = pyrf_event__type[event->header.type];
 	pevent = PyObject_New(struct pyrf_event, ptype);
@@ -1199,8 +1205,10 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
 		return NULL;
 
 	md = get_md(evlist, cpu);
-	if (!md)
+	if (!md) {
+		PyErr_Format(PyExc_TypeError, "Unknown CPU '%d'", cpu);
 		return NULL;
+	}
 
 	if (perf_mmap__read_init(&md->core) < 0)
 		goto end;
-- 
2.50.1.552.g942d659e1b-goog