[PATCH 5.15 47/69] tcp: Fix data-races around sk_pacing_rate.

[Greg Kroah-Hartman]

From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>

[ Upstream commit 59bf6c65a09fff74215517aecffbbdcd67df76e3 ]

While reading sysctl_tcp_pacing_(ss|ca)_ratio, they can be changed
concurrently.  Thus, we need to add READ_ONCE() to their readers.

Fixes: 43e122b014c9 ("tcp: refine pacing rate determination")
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 net/ipv4/tcp_input.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 018be3f346e6..566745f527fe 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -902,9 +902,9 @@ static void tcp_update_pacing_rate(struct sock *sk)
 	 *	 end of slow start and should slow down.
 	 */
 	if (tcp_snd_cwnd(tp) < tp->snd_ssthresh / 2)
-		rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio;
+		rate *= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pacing_ss_ratio);
 	else
-		rate *= sock_net(sk)->ipv4.sysctl_tcp_pacing_ca_ratio;
+		rate *= READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_pacing_ca_ratio);
 
 	rate *= max(tcp_snd_cwnd(tp), tp->packets_out);
 
-- 
2.35.1