Patchwork [v2,2/4] sctp: fix association hangs due to reneging packets below the cumulative TSN ACK point

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Submitter Roberts, Lee A.
Date Feb. 27, 2013, 6:54 p.m.
Message ID <1361991273-30578-3-git-send-email-lee.roberts@hp.com>
Download mbox | patch
Permalink /patch/223679/
State Changes Requested
Delegated to: David Miller
Headers show

Comments

Roberts, Lee A. - Feb. 27, 2013, 6:54 p.m.
From: "Lee A. Roberts" <lee.roberts@hp.com>

Resolve SCTP association hangs observed during SCTP stress
testing.  Observable symptoms include communications hangs
with data being held in the association reassembly and/or lobby
(ordering) queues.  Close examination of reassembly queue shows
missing packets.

In sctp_ulpq_renege_list(), do not renege packets below the
cumulative TSN ACK point.

Signed-off-by: Lee A. Roberts <lee.roberts@hp.com>
---
 net/sctp/ulpqueue.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)
Neil Horman - Feb. 28, 2013, 2:33 p.m.
On Wed, Feb 27, 2013 at 11:54:31AM -0700, Lee A. Roberts wrote:
> From: "Lee A. Roberts" <lee.roberts@hp.com>
> 
> Resolve SCTP association hangs observed during SCTP stress
> testing.  Observable symptoms include communications hangs
> with data being held in the association reassembly and/or lobby
> (ordering) queues.  Close examination of reassembly queue shows
> missing packets.
> 
> In sctp_ulpq_renege_list(), do not renege packets below the
> cumulative TSN ACK point.
> 
> Signed-off-by: Lee A. Roberts <lee.roberts@hp.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>

> 
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Patch

diff --git a/net/sctp/ulpqueue.c b/net/sctp/ulpqueue.c
index ada1746..63afddc 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -969,11 +969,16 @@  static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
 
 	tsnmap = &ulpq->asoc->peer.tsn_map;
 
-	while ((skb = __skb_dequeue_tail(list)) != NULL) {
-		freed += skb_headlen(skb);
+	while ((skb = skb_peek_tail(list)) != NULL) {
 		event = sctp_skb2event(skb);
 		tsn = event->tsn;
 
+		/* Don't renege below the Cumulative TSN ACK Point. */
+		if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
+			break;
+
+		__skb_unlink(skb, list);
+		freed += skb_headlen(skb);
 		sctp_ulpevent_free(event);
 		sctp_tsnmap_renege(tsnmap, tsn);
 		if (freed >= needed)