perf map: Convert map.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/1487691303-31858-6-git-send-email-elena.reshetova@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 0a943e7b1ea7fc745485f016875395e91feca8c8..f0e2428efd0bd6c7f2708e245efaf0e13778cf01 100644 (file)
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -141,7 +141,7 @@ void map__init(struct map *map, enum map_type type,
        RB_CLEAR_NODE(&map->rb_node);
        map->groups   = NULL;
        map->erange_warned = false;
-       atomic_set(&map->refcnt, 1);
+       refcount_set(&map->refcnt, 1);
 }
 
 struct map *map__new(struct machine *machine, u64 start, u64 len,
@@ -255,7 +255,7 @@ void map__delete(struct map *map)
 
 void map__put(struct map *map)
 {
-       if (map && atomic_dec_and_test(&map->refcnt))
+       if (map && refcount_dec_and_test(&map->refcnt))
                map__delete(map);
 }
 
@@ -354,7 +354,7 @@ struct map *map__clone(struct map *from)
        struct map *map = memdup(from, sizeof(*map));
 
        if (map != NULL) {
-               atomic_set(&map->refcnt, 1);
+               refcount_set(&map->refcnt, 1);
                RB_CLEAR_NODE(&map->rb_node);
                dso__get(map->dso);
                map->groups = NULL;

diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index abdacf800c98a78148565f23b7d9b4c916cbacaf..9545ff343ec564e698bb4112c62dce9397e84274 100644 (file)
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -1,7 +1,7 @@
 #ifndef __PERF_MAP_H
 #define __PERF_MAP_H
 
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/compiler.h>
 #include <linux/list.h>
 #include <linux/rbtree.h>
@@ -51,7 +51,7 @@ struct map {
 
        struct dso              *dso;
        struct map_groups       *groups;
-       atomic_t                refcnt;
+       refcount_t              refcnt;
 };
 
 struct kmap {
@@ -150,7 +150,7 @@ struct map *map__clone(struct map *map);
 static inline struct map *map__get(struct map *map)
 {
        if (map)
-               atomic_inc(&map->refcnt);
+               refcount_inc(&map->refcnt);
        return map;
 }