[PATCH] perf map: Fix refcount errors on Arm with -DREFCNT_CHECKING=1

From: James Clark
Date: Mon Jun 12 2023 - 11:05:30 EST


When quitting after running a perf report, the refcount checker finds
some double frees. The issue is that map__put() is called on a function
argument so it removes the refcount wrapper that someone else was using.

Fix it by only calling map__put() on a reference that is owned by this
function.

Signed-off-by: James Clark <james.clark@xxxxxxx>
---
tools/perf/util/symbol-elf.c | 9 +++++----
tools/perf/util/symbol.c | 9 +++++----
2 files changed, 10 insertions(+), 8 deletions(-)

diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 63882a4db5c7..ec0d7810bbb0 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -1365,6 +1365,7 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
struct dso *curr_dso = *curr_dsop;
struct map *curr_map;
char dso_name[PATH_MAX];
+ struct map *map_ref;

/* Adjust symbol to map to file offset */
if (adjust_kernel_syms)
@@ -1390,10 +1391,10 @@ static int dso__process_kernel_symbol(struct dso *dso, struct map *map,
if (kmaps) {
int err;

- map__get(map);
- maps__remove(kmaps, map);
- err = maps__insert(kmaps, map);
- map__put(map);
+ map_ref = map__get(map);
+ maps__remove(kmaps, map_ref);
+ err = maps__insert(kmaps, map_ref);
+ map__put(map_ref);
if (err)
return err;
}
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 6b9c55784b56..b3034fd5c0af 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1368,6 +1368,7 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
int err, fd;
char kcore_filename[PATH_MAX];
u64 stext;
+ struct map *map_ref;

if (!kmaps)
return -EINVAL;
@@ -1464,10 +1465,10 @@ static int dso__load_kcore(struct dso *dso, struct map *map,
map__set_map_ip(map, map__map_ip_ptr(new_map));
map__set_unmap_ip(map, map__unmap_ip_ptr(new_map));
/* Ensure maps are correctly ordered */
- map__get(map);
- maps__remove(kmaps, map);
- err = maps__insert(kmaps, map);
- map__put(map);
+ map_ref = map__get(map);
+ maps__remove(kmaps, map_ref);
+ err = maps__insert(kmaps, map_ref);
+ map__put(map_ref);
map__put(new_map);
if (err)
goto out_err;
--
2.34.1