[PATCH 5/9] tools: convert map.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 | 6 +++---
 tools/perf/util/map.h | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 0a943e7..f0e2428 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -141,7 +141,7 @@ void map__init(struct map *map, enum map_type type,
        RB_CLEAR_NODE(&map->rb_node);
        map->groups   = NULL;
        map->erange_warned = false;
-       atomic_set(&map->refcnt, 1);
+       refcount_set(&map->refcnt, 1);
 }
 
 struct map *map__new(struct machine *machine, u64 start, u64 len,
@@ -255,7 +255,7 @@ void map__delete(struct map *map)
 
 void map__put(struct map *map)
 {
-       if (map && atomic_dec_and_test(&map->refcnt))
+       if (map && refcount_dec_and_test(&map->refcnt))
                map__delete(map);
 }
 
@@ -354,7 +354,7 @@ struct map *map__clone(struct map *from)
        struct map *map = memdup(from, sizeof(*map));
 
        if (map != NULL) {
-               atomic_set(&map->refcnt, 1);
+               refcount_set(&map->refcnt, 1);
                RB_CLEAR_NODE(&map->rb_node);
                dso__get(map->dso);
                map->groups = NULL;
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index abdacf8..9545ff3 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -1,7 +1,7 @@
 #ifndef __PERF_MAP_H
 #define __PERF_MAP_H
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/rbtree.h>
@@ -51,7 +51,7 @@ struct map {
 
        struct dso              *dso;
        struct map_groups       *groups;
-       atomic_t                refcnt;
+       refcount_t              refcnt;
 };
 
 struct kmap {
@@ -150,7 +150,7 @@ struct map *map__clone(struct map *map);
 static inline struct map *map__get(struct map *map)
 {
        if (map)
-               atomic_inc(&map->refcnt);
+               refcount_inc(&map->refcnt);
        return map;
 }
 
-- 
2.7.4