From aa2ca5b5629dad5c3a238550464c0b731930741d Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima Date: Wed, 20 Jul 2022 09:50:16 -0700 Subject: [PATCH] tcp: Fix a data-race around sysctl_tcp_nometrics_save. commit 8499a2454d9e8a55ce616ede9f9580f36fd5b0f3 upstream. While reading sysctl_tcp_nometrics_save, 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: Greg Kroah-Hartman --- net/ipv4/tcp_metrics.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp_metrics.c b/net/ipv4/tcp_metrics.c index a501150..9dcc418 100644 --- a/net/ipv4/tcp_metrics.c +++ b/net/ipv4/tcp_metrics.c @@ -329,7 +329,7 @@ void tcp_update_metrics(struct sock *sk) int m; sk_dst_confirm(sk); - if (net->ipv4.sysctl_tcp_nometrics_save || !dst) + if (READ_ONCE(net->ipv4.sysctl_tcp_nometrics_save) || !dst) return; rcu_read_lock(); -- 2.7.4