This is a note to let you know that I've just added the patch titled tcp: Fix data-races around sysctl_tcp_moderate_rcvbuf. to the 5.10-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: tcp-fix-data-races-around-sysctl_tcp_moderate_rcvbuf.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 780476488844e070580bfc9e3bc7832ec1cea883 Mon Sep 17 00:00:00 2001 From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Date: Wed, 20 Jul 2022 09:50:18 -0700 Subject: tcp: Fix data-races around sysctl_tcp_moderate_rcvbuf. From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> commit 780476488844e070580bfc9e3bc7832ec1cea883 upstream. While reading sysctl_tcp_moderate_rcvbuf, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/tcp_input.c | 2 +- net/mptcp/protocol.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -693,7 +693,7 @@ void tcp_rcv_space_adjust(struct sock *s * <prev RTT . ><current RTT .. ><next RTT .... > */ - if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && + if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { int rcvmem, rcvbuf; u64 rcvwin, grow; --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1421,7 +1421,7 @@ static void mptcp_rcv_space_adjust(struc if (msk->rcvq_space.copied <= msk->rcvq_space.space) goto new_measure; - if (sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf && + if (READ_ONCE(sock_net(sk)->ipv4.sysctl_tcp_moderate_rcvbuf) && !(sk->sk_userlocks & SOCK_RCVBUF_LOCK)) { int rcvmem, rcvbuf; u64 rcvwin, grow; Patches currently in stable-queue which might be from kuniyu@xxxxxxxxxx are queue-5.10/tcp-fix-a-data-race-around-sysctl_tcp_app_win.patch queue-5.10/tcp-fix-a-data-race-around-sysctl_tcp_limit_output_bytes.patch queue-5.10/tcp-fix-a-data-race-around-sysctl_tcp_nometrics_save.patch queue-5.10/tcp-fix-data-races-around-sysctl_tcp_no_ssthresh_metrics_save.patch queue-5.10/tcp-fix-a-data-race-around-sysctl_tcp_adv_win_scale.patch queue-5.10/tcp-fix-a-data-race-around-sysctl_tcp_frto.patch queue-5.10/tcp-fix-data-races-around-sysctl_tcp_dsack.patch queue-5.10/tcp-fix-a-data-race-around-sysctl_tcp_challenge_ack_limit.patch queue-5.10/tcp-fix-data-races-around-sysctl_tcp_moderate_rcvbuf.patch queue-5.10/net-ping6-fix-memleak-in-ipv6_renew_options.patch