static void proc_set_tty(struct tty_struct *tty)
{
	spin_lock_irq(&current->sighand->siglock);
	__proc_set_tty(tty);
	spin_unlock_irq(&current->sighand->siglock);
}

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.