perf tools: Splice events onto evlist even on error

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@google.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Song Liu <songliubraving@fb.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yonghong Song <yhs@fb.com>
Cc: bpf@vger.kernel.org
Cc: clang-built-linux@googlegroups.com
Cc: netdev@vger.kernel.org
Link: http://lore.kernel.org/lkml/20191025180827.191916-5-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index db882f630f7e8e6bb7993bfb883e79b4e61c88f8..d36b8129b27a2978dae2e2576ffc9e8828a73455 100644 (file)
--- 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;