Re: [PATCH v2] perf ksymbol: fix memory leak: decrease refcount of map and dso
From: Arnaldo Carvalho de Melo <acme@kernel.org>
Date: 2021-06-16 18:12:50
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Em Sat, Jun 12, 2021 at 07:37:48PM +0200, Riccardo Mancini escreveu:
ASan reported a memory leak of BPF-related ksymbols map and dso. The leak is caused by refount never reaching 0, due to missing __put calls in the function machine__process_ksymbol_register. Once the dso is inserted in the map, dso__put should be called (map__new2 increases the refcount to 2). The same thing applies for the map when it's inserted into maps (maps__insert increases the refcount to 2).
Thanks, applied. - Arnaldo
quoted hunk ↗ jump to hunk
$ sudo ./perf record -- sleep 5 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.025 MB perf.data (8 samples) ] ================================================================= ==297735==ERROR: LeakSanitizer: detected memory leaks Direct leak of 6992 byte(s) in 19 object(s) allocated from: #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7) #1 0x8e4e53 in map__new2 /home/user/linux/tools/perf/util/map.c:216:20 #2 0x8cf68c in machine__process_ksymbol_register /home/user/linux/tools/perf/util/machine.c:778:10 [...] Indirect leak of 8702 byte(s) in 19 object(s) allocated from: #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7) #1 0x8728d7 in dso__new_id /home/user/linux/tools/perf/util/dso.c:1256:20 #2 0x872015 in dso__new /home/user/linux/tools/perf/util/dso.c:1295:9 #3 0x8cf623 in machine__process_ksymbol_register /home/user/linux/tools/perf/util/machine.c:774:21 [...] Indirect leak of 1520 byte(s) in 19 object(s) allocated from: #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7) #1 0x87b3da in symbol__new /home/user/linux/tools/perf/util/symbol.c:269:23 #2 0x888954 in map__process_kallsym_symbol /home/user/linux/tools/perf/util/symbol.c:710:8 [...] Indirect leak of 1406 byte(s) in 19 object(s) allocated from: #0 0x4f43c7 in calloc (/home/user/linux/tools/perf/perf+0x4f43c7) #1 0x87b3da in symbol__new /home/user/linux/tools/perf/util/symbol.c:269:23 #2 0x8cfbd8 in machine__process_ksymbol_register /home/user/linux/tools/perf/util/machine.c:803:8 [...] Signed-off-by: Riccardo Mancini <redacted> --- tools/perf/util/machine.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 3ff4936a15a4..da19be7da284 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c@@ -776,10 +776,10 @@ static int machine__process_ksymbol_register(struct machine *machine, if (dso) { dso->kernel = DSO_SPACE__KERNEL; map = map__new2(0, dso); + dso__put(dso); } if (!dso || !map) { - dso__put(dso); return -ENOMEM; }@@ -792,6 +792,7 @@ static int machine__process_ksymbol_register(struct machine *machine, map->start = event->ksymbol.addr; map->end = map->start + event->ksymbol.len; maps__insert(&machine->kmaps, map); + map__put(map); dso__set_loaded(dso); if (is_bpf_image(event->ksymbol.name)) {-- 2.23.0
-- - Arnaldo