commit
3e4006f0b86a5ae5eb0e8215f9a9e1db24506977 upstream.
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@codemonkey.org.uk>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
__tcp_v6_send_check(skb, &treq->loc_addr, &treq->rmt_addr);
ipv6_addr_copy(&fl6.daddr, &treq->rmt_addr);
+ rcu_read_lock();
err = ip6_xmit(sk, skb, &fl6, rcu_dereference(np->opt),
np->tclass);
+ rcu_read_unlock();
err = net_xmit_eval(err);
}