[PATCH 34/63] perf tools: Splice events onto evlist even on error

[Arnaldo Carvalho de Melo]

From: Ian Rogers <irogers@xxxxxxxxxx>

If event parsing fails the event list is leaked, instead splice the list
onto the out result and let the caller cleanup.

An example input for parse_events found by libFuzzer that reproduces
this memory leak is 'm{'.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
Cc: John Garry <john.garry@xxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Martin KaFai Lau <kafai@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Song Liu <songliubraving@xxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Cc: Yonghong Song <yhs@xxxxxx>
Cc: bpf@xxxxxxxxxxxxxxx
Cc: clang-built-linux@xxxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Link: http://lore.kernel.org/lkml/20191025180827.191916-5-irogers@xxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/parse-events.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index db882f630f7e..d36b8129b27a 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1927,15 +1927,20 @@ int parse_events(struct evlist *evlist, const char *str,
 
 	ret = parse_events__scanner(str, &parse_state, PE_START_EVENTS);
 	perf_pmu__parse_cleanup();
+
+	if (!ret && list_empty(&parse_state.list)) {
+		WARN_ONCE(true, "WARNING: event parser found nothing\n");
+		return -1;
+	}
+
+	/*
+	 * Add list to the evlist even with errors to allow callers to clean up.
+	 */
+	perf_evlist__splice_list_tail(evlist, &parse_state.list);
+
 	if (!ret) {
 		struct evsel *last;
 
-		if (list_empty(&parse_state.list)) {
-			WARN_ONCE(true, "WARNING: event parser found nothing\n");
-			return -1;
-		}
-
-		perf_evlist__splice_list_tail(evlist, &parse_state.list);
 		evlist->nr_groups += parse_state.nr_groups;
 		last = evlist__last(evlist);
 		last->cmdline_group_boundary = true;
-- 
2.21.0