| From | Greg Kroah-Hartman <> | Subject | [PATCH 3.12 19/83] net-tcp: fix panic in tcp_fastopen_cache_set() | Date | Fri, 6 Dec 2013 13:51:09 -0800 |
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3.12-stable review patch. If anyone has any objections, please let me know.
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From: Eric Dumazet <edumazet@google.com>
[ Upstream commit dccf76ca6b626c0c4a4e09bb221adee3270ab0ef ]
We had some reports of crashes using TCP fastopen, and Dave Jones gave a nice stack trace pointing to the error.
Issue is that tcp_get_metrics() should not be called with a NULL dst
Fixes: 1fe4c481ba637 ("net-tcp: Fast Open client - cookie cache") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: Dave Jones <davej@redhat.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: Yuchung Cheng <ycheng@google.com> Tested-by: Dave Jones <davej@fedoraproject.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- net/ipv4/tcp_metrics.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
--- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -659,10 +659,13 @@ void tcp_fastopen_cache_get(struct sock void tcp_fastopen_cache_set(struct sock *sk, u16 mss, struct tcp_fastopen_cookie *cookie, bool syn_lost) { + struct dst_entry *dst = __sk_dst_get(sk); struct tcp_metrics_block *tm; + if (!dst) + return; rcu_read_lock(); - tm = tcp_get_metrics(sk, __sk_dst_get(sk), true); + tm = tcp_get_metrics(sk, dst, true); if (tm) { struct tcp_fastopen_metrics *tfom = &tm->tcpm_fastopen;
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