This is a note to let you know that I've just added the patch titled
net: Fix a data-race around sysctl_net_busy_read.
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-fix-a-data-race-around-sysctl_net_busy_read.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit bacef6bad880c82f422d7aa8d0fde88dce677a0b
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Tue Aug 23 10:46:52 2022 -0700
net: Fix a data-race around sysctl_net_busy_read.
[ 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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/core/sock.c b/net/core/sock.c
index 1845a37d9f7e1..e4b28c10901ec 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -2508,7 +2508,7 @@ 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 = ~0U;
