From: Kuniyuki Iwashima <kuniyu@amazon.com> stable inclusion from stable-v4.19.254 commit d4a90eb32681c79a140ff2600b52fce291cf4e91 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5Q0SQ CVE: NA -------------------------------- [ Upstream commit 1a63cb91f0c2fcdeced6d6edee8d1d886583d139 ] While reading sysctl_tcp_retrans_collapse, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") 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> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- net/ipv4/tcp_output.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c index 3ab8c8c72beb..d6d979c127fe 100644 --- a/net/ipv4/tcp_output.c +++ b/net/ipv4/tcp_output.c @@ -2869,7 +2869,7 @@ static void tcp_retrans_try_collapse(struct sock *sk, struct sk_buff *to, struct sk_buff *skb = to, *tmp; bool first = true; - if (!sock_net(sk)->ipv4.sysctl_tcp_retrans_collapse) + if (!READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_retrans_collapse)) return; if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_SYN) return; -- 2.25.1