[PATCH v3 4/6] perf maps: Get map before returning in maps__find_next_entry

[Ian Rogers]

Finding a map is done under a lock, returning the map without a
reference count means it can be removed without notice and causing
uses after free. Grab a reference count to the map within the lock
region and return this. Fix up locations that need a map__put
following this.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
 tools/perf/util/machine.c | 4 +++-
 tools/perf/util/maps.c    | 2 +-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 7031f6fddcae..4911734411b5 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1761,8 +1761,10 @@ int machine__create_kernel_maps(struct machine *machine)
 		struct map *next = maps__find_next_entry(machine__kernel_maps(machine),
 							 machine__kernel_map(machine));
 
-		if (next)
+		if (next) {
 			machine__set_kernel_mmap(machine, start, map__start(next));
+			map__put(next);
+		}
 	}
 
 out_put:
diff --git a/tools/perf/util/maps.c b/tools/perf/util/maps.c
index ea8fa684e8c6..df0c8041899e 100644
--- a/tools/perf/util/maps.c
+++ b/tools/perf/util/maps.c
@@ -962,7 +962,7 @@ struct map *maps__find_next_entry(struct maps *maps, struct map *map)
 	down_read(maps__lock(maps));
 	i = maps__by_address_index(maps, map);
 	if (i < maps__nr_maps(maps))
-		result = maps__maps_by_address(maps)[i]; // TODO: map__get
+		result = map__get(maps__maps_by_address(maps)[i]);
 
 	up_read(maps__lock(maps));
 	return result;
-- 
2.43.0.687.g38aa6559b0-goog