Patch "sctp: only update outstanding_bytes for transmitted queue when doing prsctp_prune" has been added to the 4.9-stable tree

Patch "sctp: only update outstanding_bytes for transmitted queue when doing prsctp_prune" has been added to the 4.9-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    sctp: only update outstanding_bytes for transmitted queue when doing prsctp_prune

to the 4.9-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:
     sctp-only-update-outstanding_bytes-for-transmitted-queue-when-doing-prsctp_prune.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Fri Feb 23 11:48:40 CET 2018
From: Xin Long <lucien.xin@gmail.com>
Date: Sat, 25 Nov 2017 21:18:34 +0800
Subject: sctp: only update outstanding_bytes for transmitted queue when doing prsctp_prune

From: Xin Long <lucien.xin@gmail.com>


[ Upstream commit d30fc5126efb0c33b7adf5966d3051db2c3d7721 ]

Now outstanding_bytes is only increased when appending chunks into one
packet and sending it at 1st time, while decreased when it is about to
move into retransmit queue. It means outstanding_bytes value is already
decreased for all chunks in retransmit queue.

However sctp_prsctp_prune_sent is a common function to check the chunks
in both transmitted and retransmit queue, it decrease outstanding_bytes
when moving a chunk into abandoned queue from either of them.

It could cause outstanding_bytes underflow, as it also decreases it's
value for the chunks in retransmit queue.

This patch fixes it by only updating outstanding_bytes for transmitted
queue when pruning queues for prsctp prio policy, the same fix is also
needed in sctp_check_transmitted.

Fixes: 8dbdf1f5b09c ("sctp: implement prsctp PRIO policy")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sctp/outqueue.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/net/sctp/outqueue.c
+++ b/net/sctp/outqueue.c
@@ -364,7 +364,8 @@ static int sctp_prsctp_prune_sent(struct
 		asoc->sent_cnt_removable--;
 		asoc->abandoned_sent[SCTP_PR_INDEX(PRIO)]++;
 
-		if (!chk->tsn_gap_acked) {
+		if (queue != &asoc->outqueue.retransmit &&
+		    !chk->tsn_gap_acked) {
 			if (chk->transport)
 				chk->transport->flight_size -=
 						sctp_data_size(chk);
@@ -1409,7 +1410,8 @@ static void sctp_check_transmitted(struc
 			/* If this chunk has not been acked, stop
 			 * considering it as 'outstanding'.
 			 */
-			if (!tchunk->tsn_gap_acked) {
+			if (transmitted_queue != &q->retransmit &&
+			    !tchunk->tsn_gap_acked) {
 				if (tchunk->transport)
 					tchunk->transport->flight_size -=
 							sctp_data_size(tchunk);


Patches currently in stable-queue which might be from lucien.xin@gmail.com are

queue-4.9/sctp-only-update-outstanding_bytes-for-transmitted-queue-when-doing-prsctp_prune.patch
queue-4.9/sctp-set-frag_point-in-sctp_setsockopt_maxseg-correctly.patch