[3.16.y-ckt stable] Patch "sctp: donot reset the overall_error_count in SHUTDOWN_RECEIVE state" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    sctp: donot reset the overall_error_count in SHUTDOWN_RECEIVE state

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt19.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From 888a6e6476abd9595410c5a7e9f5fdcad18073c4 Mon Sep 17 00:00:00 2001
From: lucien <lucien.xin at gmail.com>
Date: Thu, 27 Aug 2015 04:52:20 +0800
Subject: sctp: donot reset the overall_error_count in SHUTDOWN_RECEIVE state

commit f648f807f61e64d247d26611e34cc97e4ed03401 upstream.

Commit f8d960524328 ("sctp: Enforce retransmission limit during shutdown")
fixed a problem with excessive retransmissions in the SHUTDOWN_PENDING by not
resetting the association overall_error_count.  This allowed the association
to better enforce assoc.max_retrans limit.

However, the same issue still exists when the association is in SHUTDOWN_RECEIVED
state.  In this state, HB-ACKs will continue to reset the overall_error_count
for the association would extend the lifetime of association unnecessarily.

This patch solves this by resetting the overall_error_count whenever the current
state is small then SCTP_STATE_SHUTDOWN_PENDING.  As a small side-effect, we
end up also handling SCTP_STATE_SHUTDOWN_ACK_SENT and SCTP_STATE_SHUTDOWN_SENT
states, but they are not really impacted because we disable Heartbeats in those
states.

Fixes: Commit f8d960524328 ("sctp: Enforce retransmission limit during shutdown")
Signed-off-by: Xin Long <lucien.xin at gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner at gmail.com>
Acked-by: Vlad Yasevich <vyasevich at gmail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 net/sctp/sm_sideeffect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/sctp/sm_sideeffect.c b/net/sctp/sm_sideeffect.c
index fef2acdf4a2e..85e6f03aeb70 100644
--- a/net/sctp/sm_sideeffect.c
+++ b/net/sctp/sm_sideeffect.c
@@ -702,7 +702,7 @@ static void sctp_cmd_transport_on(sctp_cmd_seq_t *cmds,
 	 * outstanding data and rely on the retransmission limit be reached
 	 * to shutdown the association.
 	 */
-	if (t->asoc->state != SCTP_STATE_SHUTDOWN_PENDING)
+	if (t->asoc->state < SCTP_STATE_SHUTDOWN_PENDING)
 		t->asoc->overall_error_count = 0;

 	/* Clear the hb_sent flag to signal that we had a good