From: Eric Dumazet <eric.dumazet@gmail.com>
Date: Fri, 4 Dec 2009 00:06:13 +0000 (-0800)
Subject: tcp: diag: Dont report negative values for rx queue
X-Git-Tag: v2.6.33-rc1~388^2~6
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=49d09007879ce7bee36ab453c73e97c00adce884;p=pandora-kernel.git

tcp: diag: Dont report negative values for rx queue

Both netlink and /proc/net/tcp interfaces can report transient
negative values for rx queue.

ss ->
State   Recv-Q Send-Q  Local Address:Port  Peer Address:Port
ESTAB   -6     6       127.0.0.1:45956     127.0.0.1:3333

netstat ->
tcp   4294967290      6 127.0.0.1:37784  127.0.0.1:3333 ESTABLISHED

This is because we dont lock socket while computing
tp->rcv_nxt - tp->copied_seq,
and another CPU can update copied_seq before rcv_next in RX path.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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