From: Eric Dumazet
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
---
David, I do not think this needs stable backport, this is a quite
minor bug. I've added the 'Fixes' tag for reference only.
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);
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