netdev - [PATCH v4 4/9] perf tools: splice events onto evlist even on error

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Message-Id: <20191025180827.191916-5-irogers@google.com>
Date:   Fri, 25 Oct 2019 11:08:22 -0700
From:   Ian Rogers <irogers@...gle.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Martin KaFai Lau <kafai@...com>,
        Song Liu <songliubraving@...com>, Yonghong Song <yhs@...com>,
        Andi Kleen <ak@...ux.intel.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        John Garry <john.garry@...wei.com>,
        linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        bpf@...r.kernel.org, clang-built-linux@...glegroups.com
Cc:     Stephane Eranian <eranian@...gle.com>,
        Ian Rogers <irogers@...gle.com>
Subject: [PATCH v4 4/9] 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@...gle.com>
---
 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 c516d0cce946..4c4c6f3e866a 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1952,15 +1952,20 @@ 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;
-- 
2.24.0.rc0.303.g954a862665-goog