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 5.15-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-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 64fd28e6e558585b066d00ac8cd29d08a2eb58b1
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Wed Jul 20 09:50:15 2022 -0700
tcp: Fix a data-race around sysctl_tcp_frto.
[ Upstream commit 706c6202a3589f290e1ef9be0584a8f4a3cc0507 ]
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: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index 1c940517f5f5..b9fd51826aea 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -2167,7 +2167,7 @@ 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;
}
