This is a note to let you know that I've just added the patch titled
tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()
to the 5.14-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-tp-undo_retrans-accounting-in-tcp_sacktag_one.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4f884f3962767877d7aabbc1ec124d2c307a4257 Mon Sep 17 00:00:00 2001
From: zhenggy <zhenggy@xxxxxxxxxxxxxxx>
Date: Tue, 14 Sep 2021 09:51:15 +0800
Subject: tcp: fix tp->undo_retrans accounting in tcp_sacktag_one()
From: zhenggy <zhenggy@xxxxxxxxxxxxxxx>
commit 4f884f3962767877d7aabbc1ec124d2c307a4257 upstream.
Commit 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit
time") may directly retrans a multiple segments TSO/GSO packet without
split, Since this commit, we can no longer assume that a retransmitted
packet is a single segment.
This patch fixes the tp->undo_retrans accounting in tcp_sacktag_one()
that use the actual segments(pcount) of the retransmitted packet.
Before that commit (10d3be569243), the assumption underlying the
tp->undo_retrans-- seems correct.
Fixes: 10d3be569243 ("tcp-tso: do not split TSO packets at retransmit time")
Signed-off-by: zhenggy <zhenggy@xxxxxxxxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Acked-by: Yuchung Cheng <ycheng@xxxxxxxxxx>
Acked-by: Neal Cardwell <ncardwell@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
@@ -1314,7 +1314,7 @@ static u8 tcp_sacktag_one(struct sock *s
if (dup_sack && (sacked & TCPCB_RETRANS)) {
if (tp->undo_marker && tp->undo_retrans > 0 &&
after(end_seq, tp->undo_marker))
- tp->undo_retrans--;
+ tp->undo_retrans = max_t(int, 0, tp->undo_retrans - pcount);
if ((sacked & TCPCB_SACKED_ACKED) &&
before(start_seq, state->reord))
state->reord = start_seq;
Patches currently in stable-queue which might be from zhenggy@xxxxxxxxxxxxxxx are
queue-5.14/tcp-fix-tp-undo_retrans-accounting-in-tcp_sacktag_one.patch
