perf map: Convert map_groups.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/1487691303-31858-7-git-send-email-elena.reshetova@intel.com
[ Did the missing conversion of tests/thread-mg-share.c too ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/tests/thread-mg-share.c b/tools/perf/tests/thread-mg-share.c
index 188b631..76686dd 100644 (file)
--- a/tools/perf/tests/thread-mg-share.c
+++ b/tools/perf/tests/thread-mg-share.c
@@ -43,7 +43,7 @@ int test__thread_mg_share(int subtest __maybe_unused)
                        leader && t1 && t2 && t3 && other);
 
        mg = leader->mg;
-       TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 4);
+       TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 4);
 
        /* test the map groups pointer is shared */
        TEST_ASSERT_VAL("map groups don't match", mg == t1->mg);
@@ -71,25 +71,25 @@ int test__thread_mg_share(int subtest __maybe_unused)
        machine__remove_thread(machine, other_leader);
 
        other_mg = other->mg;
-       TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&other_mg->refcnt), 2);
+       TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&other_mg->refcnt), 2);
 
        TEST_ASSERT_VAL("map groups don't match", other_mg == other_leader->mg);
 
        /* release thread group */
        thread__put(leader);
-       TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 3);
+       TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 3);
 
        thread__put(t1);
-       TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 2);
+       TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 2);
 
        thread__put(t2);
-       TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&mg->refcnt), 1);
+       TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&mg->refcnt), 1);
 
        thread__put(t3);
 
        /* release other group  */
        thread__put(other_leader);
-       TEST_ASSERT_EQUAL("wrong refcnt", atomic_read(&other_mg->refcnt), 1);
+       TEST_ASSERT_EQUAL("wrong refcnt", refcount_read(&other_mg->refcnt), 1);
 
        thread__put(other);
 

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index f0e2428..1d9ebcf 100644 (file)
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -485,7 +485,7 @@ void map_groups__init(struct map_groups *mg, struct machine *machine)
                maps__init(&mg->maps[i]);
        }
        mg->machine = machine;
-       atomic_set(&mg->refcnt, 1);
+       refcount_set(&mg->refcnt, 1);
 }
 
 static void __maps__purge(struct maps *maps)
@@ -547,7 +547,7 @@ void map_groups__delete(struct map_groups *mg)
 
 void map_groups__put(struct map_groups *mg)
 {
-       if (mg && atomic_dec_and_test(&mg->refcnt))
+       if (mg && refcount_dec_and_test(&mg->refcnt))
                map_groups__delete(mg);
 }
 

diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index 9545ff3..c8a5a64 100644 (file)
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -67,7 +67,7 @@ struct maps {
 struct map_groups {
        struct maps      maps[MAP__NR_TYPES];
        struct machine   *machine;
-       atomic_t         refcnt;
+       refcount_t       refcnt;
 };
 
 struct map_groups *map_groups__new(struct machine *machine);
@@ -77,7 +77,7 @@ bool map_groups__empty(struct map_groups *mg);
 static inline struct map_groups *map_groups__get(struct map_groups *mg)
 {
        if (mg)
-               atomic_inc(&mg->refcnt);
+               refcount_inc(&mg->refcnt);
        return mg;
 }