[tip: perf/core] perf scripting engines: Iterate on tep event arrays directly

* [tip: perf/core] perf scripting engines: Iterate on tep event arrays directly
       [not found] <20191017153733.630cd5eb@gandalf.local.home>
@ 2019-10-21 23:19 ` tip-bot2 for Steven Rostedt (VMware)
  2019-11-06 18:14 ` [tip: perf/urgent] " tip-bot2 for Steven Rostedt (VMware)
  1 sibling, 0 replies; 2+ messages in thread
From: tip-bot2 for Steven Rostedt (VMware) @ 2019-10-21 23:19 UTC (permalink / raw)
  To: linux-tip-commits
  Cc: Daniel Bristot de Oliveira, Steven Rostedt (VMware),
	Arnaldo Carvalho de Melo, Andrew Morton, Jiri Olsa, Namhyung Kim,
	Tzvetomir Stoyanov, linux-trace-devel, Ingo Molnar,
	Borislav Petkov, linux-kernel

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     a5e05abc6b8d81148b35cd8632a4a6252383d968
Gitweb:        https://git.kernel.org/tip/a5e05abc6b8d81148b35cd8632a4a6252383d968
Author:        Steven Rostedt (VMware) <rostedt@goodmis.org>
AuthorDate:    Thu, 17 Oct 2019 17:05:22 -04:00
Committer:     Arnaldo Carvalho de Melo <acme@redhat.com>
CommitterDate: Fri, 18 Oct 2019 12:07:46 -03:00

perf scripting engines: Iterate on tep event arrays directly

Instead of calling a useless (and broken) helper function to get the
next event of a tep event array, just get the array directly and iterate
over it.

Note, the broken part was from trace_find_next_event() which after this
will no longer be used, and can be removed.

Committer notes:

This fixes a segfault when generating python scripts from perf.data
files with multiple tracepoint events, i.e. the following use case is
fixed by this patch:

  # perf record -e sched:* sleep 1
  [ perf record: Woken up 31 times to write data ]
  [ perf record: Captured and wrote 0.031 MB perf.data (9 samples) ]
  # perf script -g python
  Segmentation fault (core dumped)
  #

Reported-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Tzvetomir Stoyanov <tstoyanov@vmware.com>
Cc: linux-trace-devel@vger.kernel.org
Link: http://lkml.kernel.org/r/20191017153733.630cd5eb@gandalf.local.home
Link: http://lore.kernel.org/lkml/20191017210636.061448713@goodmis.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/scripting-engines/trace-event-perl.c   |  8 ++++++--
 tools/perf/util/scripting-engines/trace-event-python.c |  9 +++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/scripting-engines/trace-event-perl.c b/tools/perf/util/scripting-engines/trace-event-perl.c
index 1596185..741f040 100644
--- a/tools/perf/util/scripting-engines/trace-event-perl.c
+++ b/tools/perf/util/scripting-engines/trace-event-perl.c
@@ -539,10 +539,11 @@ static int perl_stop_script(void)
 
 static int perl_generate_script(struct tep_handle *pevent, const char *outfile)
 {
+	int i, not_first, count, nr_events;
+	struct tep_event **all_events;
 	struct tep_event *event = NULL;
 	struct tep_format_field *f;
 	char fname[PATH_MAX];
-	int not_first, count;
 	FILE *ofp;
 
 	sprintf(fname, "%s.pl", outfile);
@@ -603,8 +604,11 @@ sub print_backtrace\n\
 }\n\n\
 ");
 
+	nr_events = tep_get_events_count(pevent);
+	all_events = tep_list_events(pevent, TEP_EVENT_SORT_ID);
 
-	while ((event = trace_find_next_event(pevent, event))) {
+	for (i = 0; all_events && i < nr_events; i++) {
+		event = all_events[i];
 		fprintf(ofp, "sub %s::%s\n{\n", event->system, event->name);
 		fprintf(ofp, "\tmy (");
 
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 5d341ef..93c03b3 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -1687,10 +1687,11 @@ static int python_stop_script(void)
 
 static int python_generate_script(struct tep_handle *pevent, const char *outfile)
 {
+	int i, not_first, count, nr_events;
+	struct tep_event **all_events;
 	struct tep_event *event = NULL;
 	struct tep_format_field *f;
 	char fname[PATH_MAX];
-	int not_first, count;
 	FILE *ofp;
 
 	sprintf(fname, "%s.py", outfile);
@@ -1735,7 +1736,11 @@ static int python_generate_script(struct tep_handle *pevent, const char *outfile
 	fprintf(ofp, "def trace_end():\n");
 	fprintf(ofp, "\tprint(\"in trace_end\")\n\n");
 
-	while ((event = trace_find_next_event(pevent, event))) {
+	nr_events = tep_get_events_count(pevent);
+	all_events = tep_list_events(pevent, TEP_EVENT_SORT_ID);
+
+	for (i = 0; all_events && i < nr_events; i++) {
+		event = all_events[i];
 		fprintf(ofp, "def %s__%s(", event->system, event->name);
 		fprintf(ofp, "event_name, ");
 		fprintf(ofp, "context, ");

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