perf tools: Fixup mmap event consumption
The tail position of the event buffer should only be modified after
actually use that event.
If not the event buffer could be invalid before use, and segment fault
occurs when invoking perf top -G.
Signed-off-by: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Cc: David Ahern <dsahern@gmail.com>
Cc: Zhouyi Zhou <yizhouzhou@ict.ac.cn>
Link: http://lkml.kernel.org/r/1382600613-32177-1-git-send-email-zhouzhouyi@gmail.com
[ Simplified the logic using exit gotos and renamed write_tail method to mmap_consume ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/python.c b/tools/perf/util/python.c
index 71b5412..2ac4bc9 100644
--- a/tools/perf/util/python.c
+++ b/tools/perf/util/python.c
@@ -822,6 +822,8 @@
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();
