[PATCH 4/9] tools: convert dso.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/dso.c | 6 +++---
 tools/perf/util/dso.h | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index 3abe337..f88aa44 100644
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -1109,7 +1109,7 @@ struct dso *dso__new(const char *name)
                INIT_LIST_HEAD(&dso->node);
                INIT_LIST_HEAD(&dso->data.open_entry);
                pthread_mutex_init(&dso->lock, NULL);
-               atomic_set(&dso->refcnt, 1);
+               refcount_set(&dso->refcnt, 1);
        }
 
        return dso;
@@ -1147,13 +1147,13 @@ void dso__delete(struct dso *dso)
 struct dso *dso__get(struct dso *dso)
 {
        if (dso)
-               atomic_inc(&dso->refcnt);
+               refcount_inc(&dso->refcnt);
        return dso;
 }
 
 void dso__put(struct dso *dso)
 {
-       if (dso && atomic_dec_and_test(&dso->refcnt))
+       if (dso && refcount_dec_and_test(&dso->refcnt))
                dso__delete(dso);
 }
 
diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index ecc4bbd..12350b1 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -1,7 +1,7 @@
 #ifndef __PERF_DSO
 #define __PERF_DSO
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/types.h>
 #include <linux/rbtree.h>
 #include <sys/types.h>
@@ -187,7 +187,7 @@ struct dso {
                void     *priv;
                u64      db_id;
        };
-       atomic_t         refcnt;
+       refcount_t       refcnt;
        char             name[0];
 };
 
-- 
2.7.4