This is a note to let you know that I've just added the patch titled
tcp: annotate data-races around tp->tcp_tx_delay
to the 5.4-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-annotate-data-races-around-tp-tcp_tx_delay.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 26a4b494c6e89c44e7b5897579e5dced37127a5b
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed Jul 19 21:28:47 2023 +0000
tcp: annotate data-races around tp->tcp_tx_delay
[ Upstream commit 348b81b68b13ebd489a3e6a46aa1c384c731c919 ]
do_tcp_getsockopt() reads tp->tcp_tx_delay while another cpu
might change its value.
Fixes: a842fe1425cb ("tcp: add optional per socket transmit delay")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230719212857.3943972-2-edumazet@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index fdf2ddc4864df..e33abcff56080 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3177,7 +3177,7 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
case TCP_TX_DELAY:
if (val)
tcp_enable_tx_delay();
- tp->tcp_tx_delay = val;
+ WRITE_ONCE(tp->tcp_tx_delay, val);
break;
default:
err = -ENOPROTOOPT;
@@ -3634,7 +3634,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
break;
case TCP_TX_DELAY:
- val = tp->tcp_tx_delay;
+ val = READ_ONCE(tp->tcp_tx_delay);
break;
case TCP_TIMESTAMP:
