From: Lee A. Roberts <lee.roberts@xxxxxx>
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.
Patch applies to linux-3.8 kernel.
Signed-off-by: Lee A. Roberts <lee.roberts@xxxxxx>
---
net/sctp/ulpqueue.c | 26 ++++++++++++++++++++++----
1 file changed, 22 insertions(+), 4 deletions(-)
diff -uprN -X linux-3.8-vanilla/Documentation/dontdiff linux-3.8-SCTP+2/net/sctp/ulpqueue.c linux-3.8-SCTP+3/net/sctp/ulpqueue.c
--- linux-3.8-SCTP+2/net/sctp/ulpqueue.c 2013-02-21 07:39:40.888281496 -0700
+++ linux-3.8-SCTP+3/net/sctp/ulpqueue.c 2013-02-21 07:55:32.817713326 -0700
@@ -962,8 +962,8 @@ static __u16 sctp_ulpq_renege_list(struc
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(struc
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;
}
--
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