This is a note to let you know that I've just added the patch titled
mptcp: fix bogus receive window shrinkage with multiple subflows
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:
mptcp-fix-bogus-receive-window-shrinkage-with-multiple-subflows.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.
>From 6bec041147a2a64a490d1f813e8a004443061b38 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Sat, 16 Sep 2023 12:52:45 +0200
Subject: mptcp: fix bogus receive window shrinkage with multiple subflows
From: Paolo Abeni <pabeni@xxxxxxxxxx>
commit 6bec041147a2a64a490d1f813e8a004443061b38 upstream.
In case multiple subflows race to update the mptcp-level receive
window, the subflow losing the race should use the window value
provided by the "winning" subflow to update it's own tcp-level
rcv_wnd.
To such goal, the current code bogusly uses the mptcp-level rcv_wnd
value as observed before the update attempt. On unlucky circumstances
that may lead to TCP-level window shrinkage, and stall the other end.
Address the issue feeding to the rcv wnd update the correct value.
Fixes: f3589be0c420 ("mptcp: never shrink offered window")
Cc: stable@xxxxxxxxxxxxxxx
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/427
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts <matthieu.baerts@xxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mptcp/options.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/net/mptcp/options.c
+++ b/net/mptcp/options.c
@@ -1248,12 +1248,13 @@ static void mptcp_set_rwin(struct tcp_so
if (rcv_wnd == rcv_wnd_old)
break;
- if (before64(rcv_wnd_new, rcv_wnd)) {
+
+ rcv_wnd_old = rcv_wnd;
+ if (before64(rcv_wnd_new, rcv_wnd_old)) {
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICTUPDATE);
goto raise_win;
}
MPTCP_INC_STATS(sock_net(ssk), MPTCP_MIB_RCVWNDCONFLICT);
- rcv_wnd_old = rcv_wnd;
}
return;
}
Patches currently in stable-queue which might be from pabeni@xxxxxxxxxx are
queue-6.1/bnxt_en-flush-xdp-for-bnxt_poll_nitroa0-s-napi.patch
queue-6.1/mptcp-fix-bogus-receive-window-shrinkage-with-multiple-subflows.patch
queue-6.1/net-hns3-add-cmdq-check-for-vf-periodic-service-task.patch
queue-6.1/igc-expose-tx-usecs-coalesce-setting-to-user.patch
queue-6.1/octeontx2-pf-do-xdp_do_flush-after-redirects.patch
queue-6.1/net-hns3-add-5ms-delay-before-clear-firmware-reset-i.patch
queue-6.1/team-fix-null-ptr-deref-when-team-device-type-is-cha.patch
queue-6.1/net-hns3-only-enable-unicast-promisc-when-mac-table-.patch
queue-6.1/net-hns3-fix-gre-checksum-offload-issue.patch
queue-6.1/net-ena-flush-xdp-packets-on-error.patch
queue-6.1/net-hns3-fix-fail-to-delete-tc-flower-rules-during-r.patch
queue-6.1/net-bridge-use-dev_stats_inc.patch
