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Commit 39bb5e62 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

net: skb_fclone_busy() needs to detect orphaned skb 



Some drivers are unable to perform TX completions in a bound time.
They instead call skb_orphan()

Problem is skb_fclone_busy() has to detect this case, otherwise
we block TCP retransmits and can freeze unlucky tcp sessions on
mostly idle hosts.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Fixes: 1f3279ae ("tcp: avoid retransmits of TCP packets hanging in host queues")
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 14051f04

include/linux/skbuff.h

+6 −2
Original line number Diff line number Diff line
@@ -799,15 +799,19 @@ struct sk_buff_fclones { 
 *	@skb: buffer

 *

 * Returns true is skb is a fast clone, and its clone is not freed.

 * Some drivers call skb_orphan() in their ndo_start_xmit(),

 * so we also check that this didnt happen.

 */

static inline bool skb_fclone_busy(const struct sk_buff *skb)

static inline bool skb_fclone_busy(const struct sock *sk,

				   const struct sk_buff *skb)

{

	const struct sk_buff_fclones *fclones;



	fclones = container_of(skb, struct sk_buff_fclones, skb1);



	return skb->fclone == SKB_FCLONE_ORIG &&

	       fclones->skb2.fclone == SKB_FCLONE_CLONE;

	       fclones->skb2.fclone == SKB_FCLONE_CLONE &&

	       fclones->skb2.sk == sk;

}



static inline struct sk_buff *alloc_skb_fclone(unsigned int size,

net/ipv4/tcp_output.c

+1 −1
Original line number Diff line number Diff line
@@ -2126,7 +2126,7 @@ bool tcp_schedule_loss_probe(struct sock *sk) 
static bool skb_still_in_host_queue(const struct sock *sk,

				    const struct sk_buff *skb)

{

	if (unlikely(skb_fclone_busy(skb))) {

	if (unlikely(skb_fclone_busy(sk, skb))) {

		NET_INC_STATS_BH(sock_net(sk),

				 LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);

		return true;

net/xfrm/xfrm_policy.c

+1 −1
Original line number Diff line number Diff line
@@ -1962,7 +1962,7 @@ static int xdst_queue_output(struct sock *sk, struct sk_buff *skb) 
	struct xfrm_policy *pol = xdst->pols[0];

	struct xfrm_policy_queue *pq = &pol->polq;



	if (unlikely(skb_fclone_busy(skb))) {

	if (unlikely(skb_fclone_busy(sk, skb))) {

		kfree_skb(skb);

		return 0;

	}