If the key is already present then free the key used for lookup.

Found with:
$ perf stat -M IO_Read_BW /bin/true

==1749112==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 32 byte(s) in 4 object(s) allocated from:
    #0 0x7f6f6fa7d7cf in __interceptor_malloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:145
    #1 0x55acecd9d7a6 in check_per_pkg util/stat.c:343
    #2 0x55acecd9d9c5 in process_counter_values util/stat.c:365
    #3 0x55acecd9e0ab in process_counter_maps util/stat.c:421
    #4 0x55acecd9e292 in perf_stat_process_counter util/stat.c:443
    #5 0x55aceca8553e in read_counters ./tools/perf/builtin-stat.c:470
    #6 0x55aceca88fe3 in __run_perf_stat ./tools/perf/builtin-stat.c:1023
    #7 0x55aceca89146 in run_perf_stat ./tools/perf/builtin-stat.c:1048
    #8 0x55aceca90858 in cmd_stat ./tools/perf/builtin-stat.c:2555
    #9 0x55acecc05fa5 in run_builtin ./tools/perf/perf.c:313
    #10 0x55acecc064fe in handle_internal_command ./tools/perf/perf.c:365
    #11 0x55acecc068bb in run_argv ./tools/perf/perf.c:409
    #12 0x55acecc070aa in main ./tools/perf/perf.c:539

Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/util/stat.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/stat.c b/tools/perf/util/stat.c
index 5c24aca0968c..c69b221f5e3e 100644
--- a/tools/perf/util/stat.c
+++ b/tools/perf/util/stat.c

@@ -345,9 +345,10 @@ static int check_per_pkg(struct evsel *counter,
 		return -ENOMEM;
 
 	*key = (uint64_t)d << 32 | s;
-	if (hashmap__find(mask, (void *)key, NULL))
+	if (hashmap__find(mask, (void *)key, NULL)) {
 		*skip = true;
-	else
+		free(key);
+	} else
 		ret = hashmap__add(mask, (void *)key, (void *)1);
 
 	return ret;

-- 
2.34.1.400.ga245620fadb-goog