[PATCH 5.18 49/88] tcp: Fix a data-race around sysctl_tcp_autocorking.

Greg Kroah-Hartman
2022-08-01T12:14:43Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit 85225e6f0a76e6745bc841c9f25169c509b573d8 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/ipv4/tcp.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 97fed1217b7f..60b46f2a6896 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);
--
2.35.1