From fad9dfefea6405039491e7e4fc21fb6e59e7d26c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Thu, 16 Apr 2015 16:12:28 -0700 Subject: [PATCH] tcp: tcp_get_info() should fetch socket fields once 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: 977cb0ecf82e ("tcp: add pacing_rate information into tcp_info") Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 18e3a12eb1b2..59c8a027721b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -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);