This is a note to let you know that I've just added the patch titled net: annotate data-race around sk->sk_txrehash to the 6.1-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-annotate-data-race-around-sk-sk_txrehash.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit d9f44a6f07319eb5d4120c8201995b917682b036 Author: Eric Dumazet <edumazet@xxxxxxxxxx> Date: Fri Jul 28 15:03:09 2023 +0000 net: annotate data-race around sk->sk_txrehash [ Upstream commit c76a0328899bbe226f8adeb88b8da9e4167bd316 ] sk_getsockopt() runs locklessly. This means sk->sk_txrehash can be read while other threads are changing its value. Other locations were handled in commit cb6cd2cec799 ("tcp: Change SYN ACK retransmit behaviour to account for rehash") Fixes: 26859240e4ee ("txhash: Add socket option to control TX hash rethink behavior") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Akhmat Karakotov <hmukos@xxxxxxxxxxxxxx> 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 9483820833c5b..77abd69c56dde 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1521,7 +1521,9 @@ int sk_setsockopt(struct sock *sk, int level, int optname, } if ((u8)val == SOCK_TXREHASH_DEFAULT) val = READ_ONCE(sock_net(sk)->core.sysctl_txrehash); - /* Paired with READ_ONCE() in tcp_rtx_synack() */ + /* Paired with READ_ONCE() in tcp_rtx_synack() + * and sk_getsockopt(). + */ WRITE_ONCE(sk->sk_txrehash, (u8)val); break; @@ -1927,7 +1929,8 @@ int sk_getsockopt(struct sock *sk, int level, int optname, break; case SO_TXREHASH: - v.val = sk->sk_txrehash; + /* Paired with WRITE_ONCE() in sk_setsockopt() */ + v.val = READ_ONCE(sk->sk_txrehash); break; default: