From: Xin Long lucien.xin@gmail.com
[ Upstream commit 3ecdda3e9ad837cf9cb41b6faa11b1af3a5abc0c ]
When adding a stream with stream reconf, the new stream firstly is in CLOSED state but new out chunks can still be enqueued. Then once gets the confirmation from the peer, the state will change to OPEN.
However, if the peer denies, it needs to roll back the stream. But when doing that, it only sets the stream outcnt back, and the chunks already in the new stream don't get purged. It caused these chunks can still be dequeued in sctp_outq_dequeue_data().
As its stream is still in CLOSE, the chunk will be enqueued to the head again by sctp_outq_head_data(). This chunk will never be sent out, and the chunks after it can never be dequeued. The assoc will be 'hung' in a dead loop of sending this chunk.
To fix it, this patch is to purge these chunks already in the new stream by calling sctp_stream_shrink_out() when failing to do the addstream reconf.
Fixes: 11ae76e67a17 ("sctp: implement receiver-side procedures for the Reconf Response Parameter") Reported-by: Ying Xu yinxu@redhat.com Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/sctp/stream.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/net/sctp/stream.c +++ b/net/sctp/stream.c @@ -1143,11 +1143,13 @@ struct sctp_chunk *sctp_process_strreset nums = ntohs(addstrm->number_of_streams); number = stream->outcnt - nums;
- if (result == SCTP_STRRESET_PERFORMED) + if (result == SCTP_STRRESET_PERFORMED) { for (i = number; i < stream->outcnt; i++) SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN; - else + } else { + sctp_stream_shrink_out(stream, number); stream->outcnt = number; + }
*evp = sctp_ulpevent_make_stream_change_event(asoc, flags, 0, nums, GFP_ATOMIC);