On Fri, Jan 12, 2018 at 11:42:22AM +0800, Jianchao Wang wrote: > Customer reported memory corruption issue on previous mlx4_en driver > version where the order-3 pages and multiple page reference counting > were still used. > > Finally, find out one of the root causes is that the HW may see stale > rx_descs due to prod db updating reaches HW before rx_desc. Especially > when cross order-3 pages boundary and update a new one, HW may write > on the pages which may has been freed and allocated again by others. > > To fix it, add a wmb between rx_desc and prod db updating to ensure > the order. Even thougth order-0 and page recycling has been introduced, > the disorder between rx_desc and prod db still could lead to corruption > on different inbound packages. > > Signed-off-by: Jianchao Wang <jianchao.w.w...@oracle.com> > drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c > b/drivers/net/ethernet/mellanox/mlx4/en_rx.c > index 85e28ef..eefa82c 100644 > +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c > @@ -555,7 +555,7 @@ static void mlx4_en_refill_rx_buffers(struct mlx4_en_priv > *priv, > break; > ring->prod++; > } while (likely(--missing)); > - > + wmb(); /* ensure rx_desc updating reaches HW before prod db updating */ > mlx4_en_update_rx_prod_db(ring); > } >
Does this need to be dma_wmb(), and should it be in mlx4_en_update_rx_prod_db ? Jason
