From c087e9480cf33672ef2c6cce4348d754988b8437 Mon Sep 17 00:00:00 2001 From: Riccardo Mancini Date: Sat, 12 Jun 2021 19:37:48 +0200 Subject: [PATCH] perf machine: Fix refcount usage when processing PERF_RECORD_KSYMBOL 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 Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Ian Rogers Cc: Jiapeng Chong Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Tommi Rantala Link: http://lore.kernel.org/lkml/20210612173751.188582-1-rickyman7@gmail.com Signed-off-by: Arnaldo Carvalho de Melo --- 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 3ff4936a15a42f..da19be7da284c2 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)) {