tcp: Fix data-races around sysctl_tcp_slow_start_after_idle.

[ Upstream commit 4845b5713ab18a1bb6e31d1fbb4d600240b8b691 ]

While reading sysctl_tcp_slow_start_after_idle, it can be changed
concurrently.  Thus, we need to add READ_ONCE() to its readers.

Fixes: 35089bb203 ("[TCP]: Add tcp_slow_start_after_idle sysctl.")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Kuniyuki Iwashima 2022-07-18 10:26:48 -07:00 committed by Greg Kroah-Hartman
parent cc133e4f4b
commit 0e3f82a03e
2 changed files with 3 additions and 3 deletions

View File

@ -1380,8 +1380,8 @@ static inline void tcp_slow_start_after_idle_check(struct sock *sk)
struct tcp_sock *tp = tcp_sk(sk);
s32 delta;
if (!sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle || tp->packets_out ||
ca_ops->cong_control)
if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) ||
tp->packets_out || ca_ops->cong_control)
return;
delta = tcp_jiffies32 - tp->lsndtime;
if (delta > inet_csk(sk)->icsk_rto)

View File

@ -1899,7 +1899,7 @@ static void tcp_cwnd_validate(struct sock *sk, bool is_cwnd_limited)
if (tp->packets_out > tp->snd_cwnd_used)
tp->snd_cwnd_used = tp->packets_out;
if (sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle &&
if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_slow_start_after_idle) &&
(s32)(tcp_jiffies32 - tp->snd_cwnd_stamp) >= inet_csk(sk)->icsk_rto &&
!ca_ops->cong_control)
tcp_cwnd_application_limited(sk);