void stop_tty(struct tty_struct *tty)
{
	unsigned long flags;

	spin_lock_irqsave(&tty->flow_lock, flags);
	__stop_tty(tty);
	spin_unlock_irqrestore(&tty->flow_lock, flags);
}

The product contains a concurrent code sequence that requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence operating concurrently.