iOS6下AVAudioPlayer内存泄露

我的视图控制器里放了一个按钮。main bundle里放了一个1.mp3，按钮每按一次就停止上次的音乐播放，开始下次音乐播放；

此代码在iOS4/5工作正常，iOS6中有严重的内存泄露。如果1.mp3有5M大，iOS6下每次播放就会有5M的内存不能释放。

我在iOS6下的使用方法错了吗？求指导

代码如下（开启ARC）：

@implementation ViewController
{
    AVAudioPlayer *_player;
}

- (void)play
{
    if (_player)
    {
        [_player stop];
        _player = nil;
    }
    
    NSString *path = [NSHomeDirectory() stringByAppendingPathComponent:@"test.app/1.mp3"];
    NSData *musicData = [[NSData alloc] initWithContentsOfFile:path];
    AVAudioPlayer *player = [[AVAudioPlayer alloc] initWithData:musicData error:nil];
    player.volume = 1;
    if (player)
    {
        _player = player;
    }
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    button.frame = CGRectMake(100, 100, 100, 100);
    [button setTitle:@"play" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(play) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
}

@end