Messages in this thread Patch in this message | | | From | Riccardo Mancini <> | Subject | [PATCH v2] perf ksymbol: fix memory leak: decrease refcount of map and dso | Date | Sat, 12 Jun 2021 19:37:48 +0200 |
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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).
$ 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 <rickyman7@gmail.com> --- 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
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