Memory leak in UITableView when scrolling on iOS 5.1

A memory leak of 48 bytes occurs for each UITableview scroll. Responsible library: libsystem_c.dylib Responsible frame: strdup.

This is only observed on iOS 5.1, and not on earlier versions. Has anyone else come across the same? Is this a bug in iOS 5.1?

the code:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath(NSIndexPath *)indexPath 
{
    NSString *cellIdentifier = [[NSString alloc] initWithString:@"fontSelectionCell"];

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
    [cellIdentifier release];

    if (cell == nil) 
    {
        cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] autorelease];
    }       

    cell.textLabel.text = [fontNameList objectAtIndex:[indexPath row]];
    cell.selectionStyle =UITableViewCellSelectionStyleGray;
    cell.textLabel.font = [UIFont systemFontOfSize:17.0];

    if ([fontName isEqualToString:cell.textLabel.text])
    {
        cell.accessoryType = UITableViewCellAccessoryCheckmark;
        cell.textLabel.textColor = [UIColor blueColor];

    }
    else
    {
        cell.accessoryType = UITableViewCellAccessoryNone;
        cell.textLabel.textColor = [UIColor blackColor]; 
    }

    return cell;
}