From: Eric Dumazet <edumazet@xxxxxxxxxx>
This patch has been added to the 3.18 stable tree. If you have any
objections, please let us know.
===============
[ Upstream commit fad9dfefea6405039491e7e4fc21fb6e59e7d26c ]
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 <edumazet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
---
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 38c2bcb..de61954 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -2639,6 +2639,7 @@ 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));
@@ -2699,10 +2700,11 @@ 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);
--
2.1.0
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