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 4.19-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-4.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit a31266443e645c02941758477f88125a8b720eef 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 79f085df52cef..cd23a8e4556ca 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -2856,7 +2856,7 @@ 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;