Patchwork [v2,3/4] sctp: fix association hangs due to errors when reneging events from the ordering queue

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Submitter Roberts, Lee A.
Date Feb. 27, 2013, 6:54 p.m.
Message ID <1361991273-30578-4-git-send-email-lee.roberts@hp.com>
Download mbox | patch
Permalink /patch/223680/
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(), events being reneged from the
ordering queue may correspond to multiple TSNs.  Identify
all affected packets; sum freed space and renege from the
tsnmap.

Signed-off-by: Lee A. Roberts <lee.roberts@hp.com>
---
 net/sctp/ulpqueue.c |   26 ++++++++++++++++++++++----
 1 file changed, 22 insertions(+), 4 deletions(-)
Neil Horman - Feb. 28, 2013, 2:34 p.m.
On Wed, Feb 27, 2013 at 11:54:32AM -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(), events being reneged from the
> ordering queue may correspond to multiple TSNs.  Identify
> all affected packets; sum freed space and renege from the
> tsnmap.
> 
> 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 63afddc..f221fbb 100644
--- a/net/sctp/ulpqueue.c
+++ b/net/sctp/ulpqueue.c
@@ -962,8 +962,8 @@  static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
 		struct sk_buff_head *list, __u16 needed)
 {
 	__u16 freed = 0;
-	__u32 tsn;
-	struct sk_buff *skb;
+	__u32 tsn, last_tsn;
+	struct sk_buff *skb, *flist, *last;
 	struct sctp_ulpevent *event;
 	struct sctp_tsnmap *tsnmap;
 
@@ -977,10 +977,28 @@  static __u16 sctp_ulpq_renege_list(struct sctp_ulpq *ulpq,
 		if (TSN_lte(tsn, sctp_tsnmap_get_ctsn(tsnmap)))
 			break;
 
-		__skb_unlink(skb, list);
+		/* Events in ordering queue may have multiple fragments
+		 * corresponding to additional TSNs.  Sum the total
+		 * freed space; find the last TSN.
+		 */
 		freed += skb_headlen(skb);
+		flist = skb_shinfo(skb)->frag_list;
+		for (last = flist; flist; flist = flist->next) {
+			last = flist;
+			freed += skb_headlen(last);
+		}
+		if (last)
+			last_tsn = sctp_skb2event(last)->tsn;
+		else
+			last_tsn = tsn;
+
+		/* Unlink the event, then renege all applicable TSNs. */
+		__skb_unlink(skb, list);
 		sctp_ulpevent_free(event);
-		sctp_tsnmap_renege(tsnmap, tsn);
+		while (TSN_lte(tsn, last_tsn)) {
+			sctp_tsnmap_renege(tsnmap, tsn);
+			tsn++;
+		}
 		if (freed >= needed)
 			return freed;
 	}