This is a note to let you know that I've just added the patch titled
tcp: annotate data-races around tp->linger2
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:
tcp-annotate-data-races-around-tp-linger2.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 e94e0409f44504d34b6f41dc533d8c1ae777761e
Author: Eric Dumazet <edumazet@xxxxxxxxxx>
Date: Wed Jul 19 21:28:53 2023 +0000
tcp: annotate data-races around tp->linger2
[ Upstream commit 9df5335ca974e688389c875546e5819778a80d59 ]
do_tcp_getsockopt() reads tp->linger2 while another cpu
might change its value.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230719212857.3943972-8-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 9f3cdcbbb7590..4711963413a49 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -3000,11 +3000,11 @@ static int do_tcp_setsockopt(struct sock *sk, int level,
case TCP_LINGER2:
if (val < 0)
- tp->linger2 = -1;
+ WRITE_ONCE(tp->linger2, -1);
else if (val > TCP_FIN_TIMEOUT_MAX / HZ)
- tp->linger2 = TCP_FIN_TIMEOUT_MAX;
+ WRITE_ONCE(tp->linger2, TCP_FIN_TIMEOUT_MAX);
else
- tp->linger2 = val * HZ;
+ WRITE_ONCE(tp->linger2, val * HZ);
break;
case TCP_DEFER_ACCEPT:
@@ -3401,7 +3401,7 @@ static int do_tcp_getsockopt(struct sock *sk, int level,
val = icsk->icsk_syn_retries ? : net->ipv4.sysctl_tcp_syn_retries;
break;
case TCP_LINGER2:
- val = tp->linger2;
+ val = READ_ONCE(tp->linger2);
if (val >= 0)
val = (val ? : READ_ONCE(net->ipv4.sysctl_tcp_fin_timeout)) / HZ;
break;
