Returning NULL for out of bound CPU or thread map items causes
internal errors. Fix by correctly setting the error to be an index
error.

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/python.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 1d9fa33d377a..2f28f71325a8 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -529,8 +529,10 @@ static PyObject *pyrf_cpu_map__item(PyObject *obj, Py_ssize_t i)
 {
 	struct pyrf_cpu_map *pcpus = (void *)obj;
 
-	if (i >= perf_cpu_map__nr(pcpus->cpus))
+	if (i >= perf_cpu_map__nr(pcpus->cpus)) {
+		PyErr_SetString(PyExc_IndexError, "Index out of range");
 		return NULL;
+	}
 
 	return Py_BuildValue("i", perf_cpu_map__cpu(pcpus->cpus, i).cpu);
 }
@@ -598,8 +600,10 @@ static PyObject *pyrf_thread_map__item(PyObject *obj, Py_ssize_t i)
 {
 	struct pyrf_thread_map *pthreads = (void *)obj;
 
-	if (i >= perf_thread_map__nr(pthreads->threads))
+	if (i >= perf_thread_map__nr(pthreads->threads)) {
+		PyErr_SetString(PyExc_IndexError, "Index out of range");
 		return NULL;
+	}
 
 	return Py_BuildValue("i", perf_thread_map__pid(pthreads->threads, i));
 }
-- 
2.50.0.727.gbf7dc18ff4-goog