4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx> commit f1693c63ab133d16994cc50f773982b5905af264 upstream. Loop transport which is self loopback, remote port congestion update isn't relevant. Infact the xmit path already ignores it. Receive path needs to do the same. Reported-by: syzbot+4c20b3866171ce8441d2@xxxxxxxxxxxxxxxxxxxxxxxxx Reviewed-by: Sowmini Varadhan <sowmini.varadhan@xxxxxxxxxx> Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/rds/loop.c | 1 + net/rds/rds.h | 5 +++++ net/rds/recv.c | 5 +++++ 3 files changed, 11 insertions(+) --- a/net/rds/loop.c +++ b/net/rds/loop.c @@ -191,4 +191,5 @@ struct rds_transport rds_loop_transport .inc_copy_to_user = rds_message_inc_copy_to_user, .inc_free = rds_loop_inc_free, .t_name = "loopback", + .t_type = RDS_TRANS_LOOP, }; --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -401,6 +401,11 @@ struct rds_notifier { int n_status; }; +/* Available as part of RDS core, so doesn't need to participate + * in get_preferred transport etc + */ +#define RDS_TRANS_LOOP 3 + /** * struct rds_transport - transport specific behavioural hooks * --- a/net/rds/recv.c +++ b/net/rds/recv.c @@ -76,6 +76,11 @@ static void rds_recv_rcvbuf_delta(struct return; rs->rs_rcv_bytes += delta; + + /* loop transport doesn't send/recv congestion updates */ + if (rs->rs_transport->t_type == RDS_TRANS_LOOP) + return; + now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs); rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "