From: Eric Dumazet <edumazet@xxxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit 3e4006f0b86a5ae5eb0e8215f9a9e1db24506977 ]
When first SYNACK is sent, we already hold rcu_read_lock(), but this
is not true if a SYNACK is retransmitted, as a timer (soft) interrupt
does not hold rcu_read_lock()
Fixes: 45f6fad84cc30 ("ipv6: add complete rcu protection around np->opt")
Reported-by: Dave Jones <davej@xxxxxxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
net/ipv6/tcp_ipv6.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 90004c6e3bff..7138ee87e07c 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -484,8 +484,10 @@ static int tcp_v6_send_synack(struct sock *sk, struct dst_entry *dst,
fl6->daddr = treq->rmt_addr;
skb_set_queue_mapping(skb, queue_mapping);
+ rcu_read_lock();
err = ip6_xmit(sk, skb, fl6, rcu_dereference(np->opt),
np->tclass);
+ rcu_read_unlock();
err = net_xmit_eval(err);
}
--
2.7.0
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