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@intel.com Signed-off-by: Hans Liljestrand ishkamiel@gmail.com Signed-off-by: Kees Cook keescook@chromium.org Signed-off-by: David Windsor dwindsor@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; };