[PATCH 3/4] perf tools: hook up perf_scripting_context->pevent

[Tom Zanussi]

Running the check-perf-trace scripts causes segfaults in both the Perl
and Python cases:

  # perf script record check-perf-trace
  # perf script -s libexec/perf-core/scripts/python/check-perf-trace.py
  trace_begin
  Segmentation fault (core dumped)

The reason is that the 'pevent' field was added to
perf_scripting_context but it wasn't hooked up with an actual pevent
in either case, so when one of the 'common' fields is accessed (in
util/trace-event-parse.c:get_common_fields()), pevent->events tries to
dereference a NULL pointer.

This sets the pevent field when the scripting context is set up.

Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
---
 tools/perf/util/scripting-engines/trace-event-perl.c   | 1 +
 tools/perf/util/scripting-engines/trace-event-python.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/tools/perf/util/scripting-engines/trace-event-perl.c b/tools/perf/util/scripting-engines/trace-event-perl.c
index f80605e..eacec85 100644
--- a/tools/perf/util/scripting-engines/trace-event-perl.c
+++ b/tools/perf/util/scripting-engines/trace-event-perl.c
@@ -292,6 +292,7 @@ static void perl_process_tracepoint(union perf_event *perf_event __maybe_unused,
 	ns = nsecs - s * NSECS_PER_SEC;
 
 	scripting_context->event_data = data;
+	scripting_context->pevent = evsel->tp_format->pevent;
 
 	ENTER;
 	SAVETMPS;
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 14683df..e87aa5d 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -265,6 +265,7 @@ static void python_process_tracepoint(union perf_event *perf_event
 	ns = nsecs - s * NSECS_PER_SEC;
 
 	scripting_context->event_data = data;
+	scripting_context->pevent = evsel->tp_format->pevent;
 
 	context = PyCObject_FromVoidPtr(scripting_context, NULL);
 
-- 
1.7.11.4

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