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tcp: tcp_get_info() should fetch socket fields once

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tcp_get_info() can be called without holding socket lock,
so any socket fields can change under us.

Use READ_ONCE() to fetch sk_pacing_rate and sk_max_pacing_rate

Fixes: 977cb0ecf8 ("tcp: add pacing_rate information into tcp_info")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2015-04-16 16:12:28 -07:00 committed by David S. Miller
parent c3ffe6d2c9
commit fad9dfefea
1 changed files with 6 additions and 4 deletions
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10
net/ipv4/tcp.c
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@ -2595,6 +2595,7 @@ void tcp_get_info(const struct sock *sk, struct tcp_info *info)
const struct tcp_sock *tp = tcp_sk(sk);
const struct inet_connection_sock *icsk = inet_csk(sk);
u32 now = tcp_time_stamp;
u32 rate;
memset(info, 0, sizeof(*info));
@ -2655,10 +2656,11 @@ void tcp_get_info(const struct sock *sk, struct tcp_info *info)
info->tcpi_total_retrans = tp->total_retrans;
info->tcpi_pacing_rate = sk->sk_pacing_rate != ~0U ?
sk->sk_pacing_rate : ~0ULL;
info->tcpi_max_pacing_rate = sk->sk_max_pacing_rate != ~0U ?
sk->sk_max_pacing_rate : ~0ULL;
rate = READ_ONCE(sk->sk_pacing_rate);
info->tcpi_pacing_rate = rate != ~0U ? rate : ~0ULL;
rate = READ_ONCE(sk->sk_max_pacing_rate);
info->tcpi_max_pacing_rate = rate != ~0U ? rate : ~0ULL;
}
EXPORT_SYMBOL_GPL(tcp_get_info);