This is a note to let you know that I've just added the patch titled

    tcp: tcp_make_synack() should clear skb->tstamp

to the 4.0-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     tcp-tcp_make_synack-should-clear-skb-tstamp.patch
and it can be found in the queue-4.0 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From foo@baz Tue Apr 21 23:10:35 CEST 2015
From: Eric Dumazet <[email protected]>
Date: Thu, 9 Apr 2015 13:31:56 -0700
Subject: tcp: tcp_make_synack() should clear skb->tstamp

From: Eric Dumazet <[email protected]>

[ Upstream commit b50edd7812852d989f2ef09dcfc729690f54a42d ]

I noticed tcpdump was giving funky timestamps for locally
generated SYNACK messages on loopback interface.

11:42:46.938990 IP 127.0.0.1.48245 > 127.0.0.2.23850: S
945476042:945476042(0) win 43690 <mss 65495,nop,nop,sackOK,nop,wscale 7>

20:28:58.502209 IP 127.0.0.2.23850 > 127.0.0.1.48245: S
3160535375:3160535375(0) ack 945476043 win 43690 <mss
65495,nop,nop,sackOK,nop,wscale 7>

This is because we need to clear skb->tstamp before
entering lower stack, otherwise net_timestamp_check()
does not set skb->tstamp.

Fixes: 7faee5c0d514 ("tcp: remove TCP_SKB_CB(skb)->when")
Signed-off-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 net/ipv4/tcp_output.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2929,6 +2929,8 @@ struct sk_buff *tcp_make_synack(struct s
        }
 #endif
 
+       /* Do not fool tcpdump (if any), clean our debris */
+       skb->tstamp.tv64 = 0;
        return skb;
 }
 EXPORT_SYMBOL(tcp_make_synack);


Patches currently in stable-queue which might be from [email protected] are

queue-4.0/bnx2x-fix-busy_poll-vs-netpoll.patch
queue-4.0/tcp-tcp_make_synack-should-clear-skb-tstamp.patch
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