tcp/dccp: fix ireq->pktopts race
authorEric Dumazet <edumazet@google.com>
Fri, 30 Oct 2015 16:46:12 +0000 (09:46 -0700)
committerDavid S. Miller <davem@davemloft.net>
Mon, 2 Nov 2015 20:38:26 +0000 (15:38 -0500)
commitce1050089c969b96c797118f9cb0cf5a421ddc69
tree96cae05caf0bddb2f7b3646efcabff06926cb13e
parent7b5654349e4728021b9301e42ae16fa11f6832c8
tcp/dccp: fix ireq->pktopts race

IPv6 request sockets store a pointer to skb containing the SYN packet
to be able to transfer it to full blown socket when 3WHS is done
(ireq->pktopts -> np->pktoptions)

As explained in commit 5e0724d027f0 ("tcp/dccp: fix hashdance race for
passive sessions"), we must transfer the skb only if we won the
hashdance race, if multiple cpus receive the 'ack' packet completing
3WHS at the same time.

Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Fixes: 079096f103fa ("tcp/dccp: install syn_recv requests into ehash table")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
net/dccp/ipv6.c
net/ipv6/tcp_ipv6.c