[PATCH 6/9] tools: convert map_groups.refcnt from atomic_t to refcount_t

[Elena Reshetova]

refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.

Signed-off-by: Elena Reshetova <elena.reshet...@intel.com>
Signed-off-by: Hans Liljestrand <ishkam...@gmail.com>
Signed-off-by: Kees Cook <keesc...@chromium.org>
Signed-off-by: David Windsor <dwind...@gmail.com>
---
 tools/perf/util/map.c | 4 ++--
 tools/perf/util/map.h | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index f0e2428..1d9ebcf 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -485,7 +485,7 @@ void map_groups__init(struct map_groups *mg, struct machine 
*machine)
                maps__init(&mg->maps[i]);
        }
        mg->machine = machine;
-       atomic_set(&mg->refcnt, 1);
+       refcount_set(&mg->refcnt, 1);
 }
 
 static void __maps__purge(struct maps *maps)
@@ -547,7 +547,7 @@ void map_groups__delete(struct map_groups *mg)
 
 void map_groups__put(struct map_groups *mg)
 {
-       if (mg && atomic_dec_and_test(&mg->refcnt))
+       if (mg && refcount_dec_and_test(&mg->refcnt))
                map_groups__delete(mg);
 }
 
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 9545ff3..c8a5a64 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -67,7 +67,7 @@ struct maps {
 struct map_groups {
        struct maps      maps[MAP__NR_TYPES];
        struct machine   *machine;
-       atomic_t         refcnt;
+       refcount_t       refcnt;
 };
 
 struct map_groups *map_groups__new(struct machine *machine);
@@ -77,7 +77,7 @@ bool map_groups__empty(struct map_groups *mg);
 static inline struct map_groups *map_groups__get(struct map_groups *mg)
 {
        if (mg)
-               atomic_inc(&mg->refcnt);
+               refcount_inc(&mg->refcnt);
        return mg;
 }
 
-- 
2.7.4