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: Dmitry Vyukov <dvyukov@google.com>
Cc: Samuel Ortiz <samuel@sortiz.org>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/irda/ircomm/ircomm_param.c b/net/irda/ircomm/ircomm_param.c
index 3c4caa60c9265dd95f62d7a3aba84d40cdba0492..5728e76ca6d51adabef2cde3e06b0b9184c2d07e 100644 (file)
--- a/net/irda/ircomm/ircomm_param.c
+++ b/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);