[PATCH 13/35] perf dso: Convert dso.refcnt from atomic_t to refcount_t

From: Arnaldo Carvalho de Melo
Date: Mon Mar 06 2017 - 14:41:05 EST


From: Elena Reshetova <elena.reshetova@xxxxxxxxx>

The 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: David Windsor <dwindsor@xxxxxxxxx>
Signed-off-by: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Signed-off-by: Kees Kook <keescook@xxxxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: David Windsor <dwindsor@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Hans Liljestrand <ishkamiel@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Kees Kook <keescook@xxxxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: alsa-devel@xxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/1487691303-31858-5-git-send-email-elena.reshetova@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
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 d38b62a700ca..42db00d78573 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 ecc4bbd3f82e..12350b171727 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];
};

--
2.9.3