This is a note to let you know that I've just added the patch titled
mptcp: fix data re-injection from stale subflow
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-data-re-injection-from-stale-subflow.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 b6c620dc43ccb4e802894e54b651cf81495e9598 Mon Sep 17 00:00:00 2001
From: Paolo Abeni <pabeni@xxxxxxxxxx>
Date: Wed, 31 Jan 2024 22:49:46 +0100
Subject: mptcp: fix data re-injection from stale subflow
From: Paolo Abeni <pabeni@xxxxxxxxxx>
commit b6c620dc43ccb4e802894e54b651cf81495e9598 upstream.
When the MPTCP PM detects that a subflow is stale, all the packet
scheduler must re-inject all the mptcp-level unacked data. To avoid
acquiring unneeded locks, it first try to check if any unacked data
is present at all in the RTX queue, but such check is currently
broken, as it uses TCP-specific helper on an MPTCP socket.
Funnily enough fuzzers and static checkers are happy, as the accessed
memory still belongs to the mptcp_sock struct, and even from a
functional perspective the recovery completed successfully, as
the short-cut test always failed.
A recent unrelated TCP change - commit d5fed5addb2b ("tcp: reorganize
tcp_sock fast path variables") - exposed the issue, as the tcp field
reorganization makes the mptcp code always skip the re-inection.
Fix the issue dropping the bogus call: we are on a slow path, the early
optimization proved once again to be evil.
Fixes: 1e1d9d6f119c ("mptcp: handle pending data on closed subflow")
Cc: stable@xxxxxxxxxxxxxxx
Closes: https://github.com/multipath-tcp/mptcp_net-next/issues/468
Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx>
Reviewed-by: Mat Martineau <martineau@xxxxxxxxxx>
Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20240131-upstream-net-20240131-mptcp-ci-issues-v1-1-4c1c11e571ff@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/mptcp/protocol.c | 3 ---
1 file changed, 3 deletions(-)
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -2336,9 +2336,6 @@ bool __mptcp_retransmit_pending_data(str
if (__mptcp_check_fallback(mptcp_sk(sk)))
return false;
- if (tcp_rtx_and_write_queues_empty(sk))
- return false;
-
/* the closing socket has some data untransmitted and/or unacked:
* some data in the mptcp rtx queue has not really xmitted yet.
* keep it simple and re-inject the whole mptcp level rtx queue
Patches currently in stable-queue which might be from pabeni@xxxxxxxxxx are
queue-6.1/mptcp-drop-the-push_pending-field.patch
queue-6.1/net-stmmac-do-not-clear-tbs-enable-bit-on-link-up-down.patch
queue-6.1/mptcp-fix-data-re-injection-from-stale-subflow.patch
queue-6.1/mptcp-get-rid-of-msk-subflow.patch
queue-6.1/selftests-mptcp-increase-timeout-to-30-min.patch
