releases/3.19.2/sock-sock_dequeue_err_skb-needs-hard-irq-safety.patch

   1 From foo@baz Wed Mar 11 11:44:33 CET 2015
   2 From: Eric Dumazet <edumazet@google.com>
   3 Date: Wed, 18 Feb 2015 05:47:55 -0800
   4 Subject: sock: sock_dequeue_err_skb() needs hard irq safety
   5
   6 From: Eric Dumazet <edumazet@google.com>
   7
   8 [ Upstream commit 997d5c3f4427f38562cbe207ce05bb25fdcb993b ]
   9
  10 Non NAPI drivers can call skb_tstamp_tx() and then sock_queue_err_skb()
  11 from hard IRQ context.
  12
  13 Therefore, sock_dequeue_err_skb() needs to block hard irq or
  14 corruptions or hangs can happen.
  15
  16 Signed-off-by: Eric Dumazet <edumazet@google.com>
  17 Fixes: 364a9e93243d1 ("sock: deduplicate errqueue dequeue")
  18 Fixes: cb820f8e4b7f7 ("net: Provide a generic socket error queue delivery method for Tx time stamps.")
  19 Signed-off-by: David S. Miller <davem@davemloft.net>
  20 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  21 ---
  22  net/core/skbuff.c |    5 +++--
  23  1 file changed, 3 insertions(+), 2 deletions(-)
  24
  25 --- a/net/core/skbuff.c
  26 +++ b/net/core/skbuff.c
  27 @@ -3623,13 +3623,14 @@ struct sk_buff *sock_dequeue_err_skb(str
  28  {
  29         struct sk_buff_head *q = &sk->sk_error_queue;
  30         struct sk_buff *skb, *skb_next;
  31 +       unsigned long flags;
  32         int err = 0;
  33
  34 -       spin_lock_bh(&q->lock);
  35 +       spin_lock_irqsave(&q->lock, flags);
  36         skb = __skb_dequeue(q);
  37         if (skb && (skb_next = skb_peek(q)))
  38                 err = SKB_EXT_ERR(skb_next)->ee.ee_errno;
  39 -       spin_unlock_bh(&q->lock);
  40 +       spin_unlock_irqrestore(&q->lock, flags);
  41
  42         sk->sk_err = err;
  43         if (err)