From 806e6d7f95a04c90039a9194042ce558b4daa2b2 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Thu, 10 Nov 2022 20:24:31 +0800 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_tw_reuse. stable inclusion from stable-v5.10.134 commit b6c189aa801a9c8749952c65038bc08d4fde8ce4 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5ZVR7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=b6c189aa801a9c8749952c65038bc08d4fde8ce4 -------------------------------- [ Upstream commit cbfc6495586a3f09f6f07d9fb3c7cafe807e3c55 ] While reading sysctl_tcp_tw_reuse, 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 Signed-off-by: David S. Miller Signed-off-by: Sasha Levin Signed-off-by: Zheng Zengkai Reviewed-by: Wei Li --- net/ipv4/tcp_ipv4.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index c854d17cf99a..16fbadb1c2a8 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -106,10 +106,10 @@ static u32 tcp_v4_init_ts_off(const struct net *net, const struct sk_buff *skb) int tcp_twsk_unique(struct sock *sk, struct sock *sktw, void *twp) { + int reuse = READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_tw_reuse); const struct inet_timewait_sock *tw = inet_twsk(sktw); const struct tcp_timewait_sock *tcptw = tcp_twsk(sktw); struct tcp_sock *tp = tcp_sk(sk); - int reuse = sock_net(sk)->ipv4.sysctl_tcp_tw_reuse; if (reuse == 2) { /* Still does not detect *everything* that goes through -- GitLab