perf parse-event: Fix memory leak in evsel->unit

[ Upstream commit b12eea5 ]

The evsel->unit borrows a pointer of pmu event or alias instead of
owns a string.  But tool event (duration_time) passes a result of
strdup() caused a leak.

It was found by ASAN during metric test:

  Direct leak of 210 byte(s) in 70 object(s) allocated from:
    #0 0x7fe366fca0b5 in strdup (/lib/x86_64-linux-gnu/libasan.so.5+0x920b5)
    Freescale#1 0x559fbbcc6ea3 in add_event_tool util/parse-events.c:414
    Freescale#2 0x559fbbcc6ea3 in parse_events_add_tool util/parse-events.c:1414
    Freescale#3 0x559fbbd8474d in parse_events_parse util/parse-events.y:439
    Freescale#4 0x559fbbcc95da in parse_events__scanner util/parse-events.c:2096
    Freescale#5 0x559fbbcc95da in __parse_events util/parse-events.c:2141
    Freescale#6 0x559fbbc28555 in check_parse_id tests/pmu-events.c:406
    Freescale#7 0x559fbbc28555 in check_parse_id tests/pmu-events.c:393
    Freescale#8 0x559fbbc28555 in check_parse_cpu tests/pmu-events.c:415
    Freescale#9 0x559fbbc28555 in test_parsing tests/pmu-events.c:498
    Freescale#10 0x559fbbc0109b in run_test tests/builtin-test.c:410
    Freescale#11 0x559fbbc0109b in test_and_print tests/builtin-test.c:440
    Freescale#12 0x559fbbc03e69 in __cmd_test tests/builtin-test.c:695
    Freescale#13 0x559fbbc03e69 in cmd_test tests/builtin-test.c:807
    Freescale#14 0x559fbbc691f4 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
    Freescale#15 0x559fbbb071a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
    Freescale#16 0x559fbbb071a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
    Freescale#17 0x559fbbb071a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
    Freescale#18 0x7fe366b68cc9 in __libc_start_main ../csu/libc-start.c:308

Fixes: f0fbb11 ("perf stat: Implement duration_time as a proper event")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20200915031819.386559-6-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>

tools/perf/util/parse-events.c

@@ -370,7 +370,7 @@ static int add_event_tool(struct list_head *list, int *idx,
 		return -ENOMEM;
 	evsel->tool_event = tool_event;
 	if (tool_event == PERF_TOOL_DURATION_TIME)
-		evsel->unit = strdup("ns");
+		evsel->unit = "ns";
 	return 0;
 }