irda: fix a potential use-after-free in ircomm_param_request

self->ctrl_skb is protected by self->spinlock, we should not
access it out of the lock. Move the debugging printk inside.
Reported-by: NDmitry Vyukov <dvyukov@google.com>
Cc: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/irda/ircomm/ircomm_param.c

@@ -134,11 +134,10 @@ int ircomm_param_request(struct ircomm_tty_cb *self, __u8 pi, int flush)
 		return -1;
 	}
 	skb_put(skb, count);
+	pr_debug("%s(), skb->len=%d\n", __func__, skb->len);
 
 	spin_unlock_irqrestore(&self->spinlock, flags);
 
-	pr_debug("%s(), skb->len=%d\n", __func__ , skb->len);
-
 	if (flush) {
 		/* ircomm_tty_do_softint will take care of the rest */
 		schedule_work(&self->tqueue);