[PATCH 1/9] tools: convert cgroup_sel.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/cgroup.c | 6 +++---
 tools/perf/util/cgroup.h | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/cgroup.c b/tools/perf/util/cgroup.c
index eafbf114..86399ed 100644
--- a/tools/perf/util/cgroup.c
+++ b/tools/perf/util/cgroup.c
@@ -127,19 +127,19 @@ static int add_cgroup(struct perf_evlist *evlist, char 
*str)
                        goto found;
                n++;
        }
-       if (atomic_read(&cgrp->refcnt) == 0)
+       if (refcount_read(&cgrp->refcnt) == 0)
                free(cgrp);
 
        return -1;
 found:
-       atomic_inc(&cgrp->refcnt);
+       refcount_inc(&cgrp->refcnt);
        counter->cgrp = cgrp;
        return 0;
 }
 
 void close_cgroup(struct cgroup_sel *cgrp)
 {
-       if (cgrp && atomic_dec_and_test(&cgrp->refcnt)) {
+       if (cgrp && refcount_dec_and_test(&cgrp->refcnt)) {
                close(cgrp->fd);
                zfree(&cgrp->name);
                free(cgrp);
diff --git a/tools/perf/util/cgroup.h b/tools/perf/util/cgroup.h
index 31f8dcd..d91966b 100644
--- a/tools/perf/util/cgroup.h
+++ b/tools/perf/util/cgroup.h
@@ -1,14 +1,14 @@
 #ifndef __CGROUP_H__
 #define __CGROUP_H__
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 
 struct option;
 
 struct cgroup_sel {
        char *name;
        int fd;
-       atomic_t refcnt;
+       refcount_t refcnt;
 };
 
 
-- 
2.7.4