On Mon, Feb 04, 2019 at 03:27:58AM +0800, Xin Long wrote:
> Now when using stream reconfig to add out streams, stream->out
> will get re-allocated, and all old streams' information will
> be copied to the new ones and the old ones will be freed.
>
> So without stream->out_curr updated, next time when trying to
> send from stream->out_curr stream, a panic would be caused.
>
> This patch is to check and update stream->out_curr when
> allocating stream_out.
>
> v1->v2:
> - define fa_index() to get elem index from stream->out_curr.
> v2->v3:
> - repost with no change.
>
> Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
> Reported-by: Ying Xu <yinxu@xxxxxxxxxx>
> Reported-by: syzbot+e33a3a138267ca119c7d@xxxxxxxxxxxxxxxxxxxxxxxxx
> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx>
> ---
> net/sctp/stream.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/net/sctp/stream.c b/net/sctp/stream.c
> index 80e0ae5..f246331 100644
> --- a/net/sctp/stream.c
> +++ b/net/sctp/stream.c
> @@ -84,6 +84,19 @@ static void fa_zero(struct flex_array *fa, size_t index, size_t count)
> }
> }
>
> +static size_t fa_index(struct flex_array *fa, void *elem, size_t count)
> +{
> + size_t index = 0;
> +
> + while (count--) {
> + if (elem == flex_array_get(fa, index))
> + break;
> + index++;
> + }
> +
> + return index;
> +}
> +
> /* Migrates chunks from stream queues to new stream queues if needed,
> * but not across associations. Also, removes those chunks to streams
> * higher than the new max.
> @@ -147,6 +160,13 @@ static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
>
> if (stream->out) {
> fa_copy(out, stream->out, 0, min(outcnt, stream->outcnt));
> + if (stream->out_curr) {
> + size_t index = fa_index(stream->out, stream->out_curr,
> + stream->outcnt);
> +
> + BUG_ON(index == stream->outcnt);
> + stream->out_curr = flex_array_get(out, index);
> + }
> fa_free(stream->out);
> }
>
> --
> 2.1.0
>
>
Acked-by: Neil Horman <nhorman@xxxxxxxxxxxxx>
