perf dso: Convert dso.refcnt from atomic_t to refcount_t

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@intel.com>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Kook <keescook@chromium.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: David Windsor <dwindsor@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Hans Liljestrand <ishkamiel@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Kook <keescook@chromium.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Matija Glavinic Pecotic <matija.glavinic-pecotic.ext@nokia.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: alsa-devel@alsa-project.org
Link: http://lkml.kernel.org/r/1487691303-31858-5-git-send-email-elena.reshetova@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index d38b62a..42db00d 100644 (file)
--- 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 (file)
--- 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];
 };