From: Kuniyuki Iwashima kuniyu@amazon.com
[ Upstream commit 7c6f2a86ca590d5187a073d987e9599985fb1c7c ]
While reading sysctl_tcp_thin_linear_timeouts, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader.
Fixes: 36e31b0af587 ("net: TCP thin linear timeouts") 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 --- net/ipv4/tcp_timer.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/ipv4/tcp_timer.c b/net/ipv4/tcp_timer.c index e905fff09fea..84069db0423a 100644 --- a/net/ipv4/tcp_timer.c +++ b/net/ipv4/tcp_timer.c @@ -545,7 +545,7 @@ void tcp_retransmit_timer(struct sock *sk) * linear-timeout retransmissions into a black hole */ if (sk->sk_state == TCP_ESTABLISHED && - (tp->thin_lto || net->ipv4.sysctl_tcp_thin_linear_timeouts) && + (tp->thin_lto || READ_ONCE(net->ipv4.sysctl_tcp_thin_linear_timeouts)) && tcp_stream_is_thin(tp) && icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { icsk->icsk_backoff = 0;