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/thread_map.c | 20 ++++++++++----------
 tools/perf/util/thread_map.h |  4 ++--
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
index 7c3fcc5..9026408 100644
--- a/tools/perf/util/thread_map.c
+++ b/tools/perf/util/thread_map.c
@@ -66,7 +66,7 @@ struct thread_map *thread_map__new_by_pid(pid_t pid)
                for (i = 0; i < items; i++)
                        thread_map__set_pid(threads, i, 
atoi(namelist[i]->d_name));
                threads->nr = items;
-               atomic_set(&threads->refcnt, 1);
+               refcount_set(&threads->refcnt, 1);
        }
 
        for (i=0; i<items; i++)
@@ -83,7 +83,7 @@ struct thread_map *thread_map__new_by_tid(pid_t tid)
        if (threads != NULL) {
                thread_map__set_pid(threads, 0, tid);
                threads->nr = 1;
-               atomic_set(&threads->refcnt, 1);
+               refcount_set(&threads->refcnt, 1);
        }
 
        return threads;
@@ -105,7 +105,7 @@ struct thread_map *thread_map__new_by_uid(uid_t uid)
                goto out_free_threads;
 
        threads->nr = 0;
-       atomic_set(&threads->refcnt, 1);
+       refcount_set(&threads->refcnt, 1);
 
        while ((dirent = readdir(proc)) != NULL) {
                char *end;
@@ -235,7 +235,7 @@ static struct thread_map *thread_map__new_by_pid_str(const 
char *pid_str)
 out:
        strlist__delete(slist);
        if (threads)
-               atomic_set(&threads->refcnt, 1);
+               refcount_set(&threads->refcnt, 1);
        return threads;
 
 out_free_namelist:
@@ -255,7 +255,7 @@ struct thread_map *thread_map__new_dummy(void)
        if (threads != NULL) {
                thread_map__set_pid(threads, 0, -1);
                threads->nr = 1;
-               atomic_set(&threads->refcnt, 1);
+               refcount_set(&threads->refcnt, 1);
        }
        return threads;
 }
@@ -300,7 +300,7 @@ struct thread_map *thread_map__new_by_tid_str(const char 
*tid_str)
        }
 out:
        if (threads)
-               atomic_set(&threads->refcnt, 1);
+               refcount_set(&threads->refcnt, 1);
        return threads;
 
 out_free_threads:
@@ -326,7 +326,7 @@ static void thread_map__delete(struct thread_map *threads)
        if (threads) {
                int i;
 
-               WARN_ONCE(atomic_read(&threads->refcnt) != 0,
+               WARN_ONCE(refcount_read(&threads->refcnt) != 0,
                          "thread map refcnt unbalanced\n");
                for (i = 0; i < threads->nr; i++)
                        free(thread_map__comm(threads, i));
@@ -337,13 +337,13 @@ static void thread_map__delete(struct thread_map *threads)
 struct thread_map *thread_map__get(struct thread_map *map)
 {
        if (map)
-               atomic_inc(&map->refcnt);
+               refcount_inc(&map->refcnt);
        return map;
 }
 
 void thread_map__put(struct thread_map *map)
 {
-       if (map && atomic_dec_and_test(&map->refcnt))
+       if (map && refcount_dec_and_test(&map->refcnt))
                thread_map__delete(map);
 }
 
@@ -423,7 +423,7 @@ static void thread_map__copy_event(struct thread_map 
*threads,
                threads->map[i].comm = strndup(event->entries[i].comm, 16);
        }
 
-       atomic_set(&threads->refcnt, 1);
+       refcount_set(&threads->refcnt, 1);
 }
 
 struct thread_map *thread_map__new_event(struct thread_map_event *event)
diff --git a/tools/perf/util/thread_map.h b/tools/perf/util/thread_map.h
index ea0ef08..bd34d7a 100644
--- a/tools/perf/util/thread_map.h
+++ b/tools/perf/util/thread_map.h
@@ -3,7 +3,7 @@
 
 #include <sys/types.h>
 #include <stdio.h>
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 
 struct thread_map_data {
        pid_t    pid;
@@ -11,7 +11,7 @@ struct thread_map_data {
 };
 
 struct thread_map {
-       atomic_t refcnt;
+       refcount_t refcnt;
        int nr;
        struct thread_map_data map[];
 };
-- 
2.7.4

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