[PATCH 5.19 073/158] net: Fix a data-race around sysctl_net_busy_read.

Greg Kroah-Hartman
2022-08-29T11:27:45Z

From: Kuniyuki Iwashima <kuniyu@amazon.com>

[ Upstream commit e59ef36f0795696ab229569c153936bfd068d21c ]

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

Fixes: 2d48d67fa8cd ("net: poll/select low latency socket support")
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/core/sock.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/core/sock.c b/net/core/sock.c
index d672e63a5c2d4..16ab5ef749c60 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -3365,7 +3365,7 @@ void sock_init_data(struct socket *sock, struct sock *sk)

#ifdef CONFIG_NET_RX_BUSY_POLL
sk->sk_napi_id = 0;
- sk->sk_ll_usec = sysctl_net_busy_read;
+ sk->sk_ll_usec = READ_ONCE(sysctl_net_busy_read);
#endif

sk->sk_max_pacing_rate = ~0UL;
--
2.35.1