[3.16.y-ckt stable] Patch "net: skb_fclone_busy() needs to detect orphaned skb" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    net: skb_fclone_busy() needs to detect orphaned skb

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt2.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From eb50347f2beb8ca22abb883656396b2df032d65b Mon Sep 17 00:00:00 2001
From: Eric Dumazet <edumazet at google.com>
Date: Thu, 30 Oct 2014 10:32:34 -0700
Subject: net: skb_fclone_busy() needs to detect orphaned skb

commit 39bb5e62867de82b269b07df900165029b928359 upstream.

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: Eric Dumazet <edumazet at google.com>
Fixes: 1f3279ae0c13 ("tcp: avoid retransmits of TCP packets hanging in host queues")
Signed-off-by: David S. Miller <davem at davemloft.net>
[ luis: backport to 3.16 provided by Eric Dumzet ]
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/ipv4/tcp_output.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 4e4932b5079b..a8794367cd20 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2082,7 +2082,8 @@ static bool skb_still_in_host_queue(const struct sock *sk,
 	const struct sk_buff *fclone = skb + 1;

 	if (unlikely(skb->fclone == SKB_FCLONE_ORIG &&
-		     fclone->fclone == SKB_FCLONE_CLONE)) {
+		     fclone->fclone == SKB_FCLONE_CLONE &&
+		     fclone->sk == sk)) {
 		NET_INC_STATS_BH(sock_net(sk),
 				 LINUX_MIB_TCPSPURIOUS_RTX_HOSTQUEUES);
 		return true;
--
2.1.0