perf python: Fix pyrf_evlist__read_on_cpu event consuming

We can't consume the event before parsing it. Under heavy load we could
get caught by kernel writer overwriting the event we're trying to parse.

Signed-off-by: Jiri Olsa <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>
This commit is contained in:
Jiri Olsa 2016-07-10 13:07:56 +02:00 • committed by Arnaldo Carvalho de Melo
commit e8968e6541

View file

@ -865,12 +865,14 @@ static PyObject *pyrf_evlist__read_on_cpu(struct pyrf_evlist *pevlist,
PyObject *pyevent = pyrf_event__new(event);
struct pyrf_event *pevent = (struct pyrf_event *)pyevent;
perf_evlist__mmap_consume(evlist, cpu);
if (pyevent == NULL)
return PyErr_NoMemory();
err = perf_evlist__parse_sample(evlist, event, &pevent->sample);
/* Consume the even only after we parsed it out. */
perf_evlist__mmap_consume(evlist, cpu);
if (err)
return PyErr_Format(PyExc_OSError,
"perf: can't parse sample, err=%d", err);