This is a note to let you know that I've just added the patch titled
tcp: Fix a data-race around sysctl_tcp_frto.
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-fix-a-data-race-around-sysctl_tcp_frto.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.
>From 706c6202a3589f290e1ef9be0584a8f4a3cc0507 Mon Sep 17 00:00:00 2001
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Wed, 20 Jul 2022 09:50:15 -0700
Subject: tcp: Fix a data-race around sysctl_tcp_frto.
From: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
commit 706c6202a3589f290e1ef9be0584a8f4a3cc0507 upstream.
While reading sysctl_tcp_frto, it can be changed concurrently.
Thus, we need to add READ_ONCE() to its reader.
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 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2030,7 +2030,7 @@ void tcp_enter_loss(struct sock *sk)
* loss recovery is underway except recurring timeout(s) on
* the same SND.UNA (sec 3.2). Disable F-RTO on path MTU probing
*/
- tp->frto = net->ipv4.sysctl_tcp_frto &&
+ tp->frto = READ_ONCE(net->ipv4.sysctl_tcp_frto) &&
(new_recovery || icsk->icsk_retransmits) &&
!inet_csk(sk)->icsk_mtup.probe_size;
}
Patches currently in stable-queue which might be from kuniyu@xxxxxxxxxx are
queue-5.4/tcp-fix-a-data-race-around-sysctl_tcp_app_win.patch
queue-5.4/tcp-fix-a-data-race-around-sysctl_tcp_nometrics_save.patch
queue-5.4/tcp-fix-a-data-race-around-sysctl_tcp_adv_win_scale.patch
queue-5.4/tcp-fix-a-data-race-around-sysctl_tcp_frto.patch
queue-5.4/tcp-fix-data-races-around-sysctl_tcp_dsack.patch
