tools lib traceevent: Fix kbuffer_read_at_offset()
When it's called with an offset less than or equal to the first event,
it'll return a garbage value since the data is not initialized.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20161001101700.29146-1-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/lib/traceevent/kbuffer-parse.c b/tools/lib/traceevent/kbuffer-parse.c
index 3bcada3..65984f1 100644
--- a/tools/lib/traceevent/kbuffer-parse.c
+++ b/tools/lib/traceevent/kbuffer-parse.c
@@ -622,6 +622,7 @@
/* Reset the buffer */
kbuffer_load_subbuffer(kbuf, kbuf->subbuffer);
+ data = kbuffer_read_event(kbuf, ts);
while (kbuf->curr < offset) {
data = kbuffer_next_event(kbuf, ts);