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_poll. 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_poll.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 d4b86a205001a659f2b217e89c6ca1a593c22024 Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Tue Aug 23 10:46:51 2022 -0700 net: Fix a data-race around sysctl_net_busy_poll. [ Upstream commit c42b7cddea47503411bfb5f2f93a4154aaffa2d9 ] While reading sysctl_net_busy_poll, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 060212928670 ("net: add low latency socket poll") 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/include/net/busy_poll.h b/include/net/busy_poll.h index c76a5e9894dac..8f42f6f3af86f 100644 --- a/include/net/busy_poll.h +++ b/include/net/busy_poll.h @@ -43,7 +43,7 @@ extern unsigned int sysctl_net_busy_poll __read_mostly; static inline bool net_busy_loop_on(void) { - return sysctl_net_busy_poll; + return READ_ONCE(sysctl_net_busy_poll); } static inline bool sk_can_busy_loop(const struct sock *sk)