From: Kuniyuki Iwashima <kuniyu@amazon.com>
Date: Wed, 20 Jul 2022 16:50:25 +0000 (-0700)
Subject: tcp: Fix a data-race around sysctl_tcp_autocorking.
X-Git-Tag: v6.6.17~7014^2~32^2~1
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=85225e6f0a76e6745bc841c9f25169c509b573d8;p=platform%2Fkernel%2Flinux-rpi.git

tcp: Fix a data-race around sysctl_tcp_autocorking.

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

Fixes: f54b311142a9 ("tcp: auto corking")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 2faaaaf..a11e5de 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -686,7 +686,7 @@ static bool tcp_should_autocork(struct sock *sk, struct sk_buff *skb,
 				int size_goal)
 {
 	return skb->len < size_goal &&
-	       sock_net(sk)->ipv4.sysctl_tcp_autocorking &&
+	       READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_autocorking) &&
 	       !tcp_rtx_queue_empty(sk) &&
 	       refcount_read(&sk->sk_wmem_alloc) > skb->truesize &&
 	       tcp_skb_can_collapse_to(skb);