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tcp: annotate data races around tp->mtu_info

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While tp->mtu_info is read while socket is owned, the write
sides happen from err handlers (tcp_v[46]_mtu_reduced)
which only own the socket spinlock.

Fixes: 563d34d057 ("tcp: dont drop MTU reduction indications")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2021-07-02 13:09:03 -07:00 committed by David S. Miller
parent 8955b90c3c
commit 561022acb1
2 changed files with 4 additions and 4 deletions
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4
net/ipv4/tcp_ipv4.c
View File

@ -342,7 +342,7 @@ void tcp_v4_mtu_reduced(struct sock *sk)
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
return; return;
mtu = tcp_sk(sk)->mtu_info; mtu = READ_ONCE(tcp_sk(sk)->mtu_info);
dst = inet_csk_update_pmtu(sk, mtu); dst = inet_csk_update_pmtu(sk, mtu);
if (!dst) if (!dst)
return; return;
@ -546,7 +546,7 @@ int tcp_v4_err(struct sk_buff *skb, u32 info)
if (sk->sk_state == TCP_LISTEN) if (sk->sk_state == TCP_LISTEN)
goto out; goto out;
tp->mtu_info = info; WRITE_ONCE(tp->mtu_info, info);
if (!sock_owned_by_user(sk)) { if (!sock_owned_by_user(sk)) {
tcp_v4_mtu_reduced(sk); tcp_v4_mtu_reduced(sk);
} else { } else {

4
net/ipv6/tcp_ipv6.c
View File

@ -352,7 +352,7 @@ static void tcp_v6_mtu_reduced(struct sock *sk)
if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE)) if ((1 << sk->sk_state) & (TCPF_LISTEN | TCPF_CLOSE))
return; return;
dst = inet6_csk_update_pmtu(sk, tcp_sk(sk)->mtu_info); dst = inet6_csk_update_pmtu(sk, READ_ONCE(tcp_sk(sk)->mtu_info));
if (!dst) if (!dst)
return; return;
@ -443,7 +443,7 @@ static int tcp_v6_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
if (!ip6_sk_accept_pmtu(sk)) if (!ip6_sk_accept_pmtu(sk))
goto out; goto out;
tp->mtu_info = ntohl(info); WRITE_ONCE(tp->mtu_info, ntohl(info));
if (!sock_owned_by_user(sk)) if (!sock_owned_by_user(sk))
tcp_v6_mtu_reduced(sk); tcp_v6_mtu_reduced(sk);
else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED, else if (!test_and_set_bit(TCP_MTU_REDUCED_DEFERRED,