Re: [PATCH 3/4] sctp: fix association hangs due to errors when reneging events from the ordering queue
From: Vlad Yasevich <hidden>
Date: 2013-02-27 14:53:34
On 02/26/2013 09:36 AM, Lee A. Roberts wrote:
From: "Lee A. Roberts" <redacted> 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 <redacted>
Acked-by: Vlad Yasevich <redacted> -vlad
quoted hunk ↗ jump to hunk
--- net/sctp/ulpqueue.c | 26 ++++++++++++++++++++++---- 1 file changed, 22 insertions(+), 4 deletions(-)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; }