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 lobby (ordering)
queue. Close examination of reassembly/ordering queues shows
duplicated packets.
In sctp_tsnmap_mark(), correct off-by-one error when calculating
gap value for tsnmap.
In sctp_tsnmap_grow(), correct off-by-one error when copying
and resizing the tsnmap. If max_tsn_seen is in the LSB of the
word, this bit can be lost, causing the corresponding packet
to be transmitted again and to be entered as a duplicate into
the SCTP reassembly/ordering queues.
Patch applies to linux-3.8 kernel.
Signed-off-by: Lee A. Roberts <lee.roberts@xxxxxx>
---
net/sctp/tsnmap.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff -uprN -X linux-3.8-vanilla/Documentation/dontdiff linux-3.8-vanilla/net/sctp/tsnmap.c linux-3.8-SCTP+1/net/sctp/tsnmap.c
--- linux-3.8-vanilla/net/sctp/tsnmap.c 2013-02-18 16:58:34.000000000 -0700
+++ linux-3.8-SCTP+1/net/sctp/tsnmap.c 2013-02-21 11:16:01.843233297 -0700
@@ -124,7 +124,7 @@ int sctp_tsnmap_mark(struct sctp_tsnmap
gap = tsn - map->base_tsn;
- if (gap >= map->len && !sctp_tsnmap_grow(map, gap))
+ if (gap >= map->len && !sctp_tsnmap_grow(map, gap + 1))
return -ENOMEM;
if (!sctp_tsnmap_has_gap(map) && gap == 0) {
@@ -369,14 +369,15 @@ static int sctp_tsnmap_grow(struct sctp_
if (gap >= SCTP_TSN_MAP_SIZE)
return 0;
- inc = ALIGN((gap - map->len),BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
+ inc = ALIGN((gap - map->len), BITS_PER_LONG) + SCTP_TSN_MAP_INCREMENT;
len = min_t(u16, map->len + inc, SCTP_TSN_MAP_SIZE);
new = kzalloc(len>>3, GFP_ATOMIC);
if (!new)
return 0;
- bitmap_copy(new, map->tsn_map, map->max_tsn_seen - map->base_tsn);
+ bitmap_copy(new, map->tsn_map,
+ map->max_tsn_seen - map->cumulative_tsn_ack_point);
kfree(map->tsn_map);
map->tsn_map = new;
map->len = len;
--
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