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

From: Elena Reshetova
Date: Tue Feb 21 2017 - 10:36:33 EST


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.reshetova@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
Signed-off-by: David Windsor <dwindsor@xxxxxxxxx>
---
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