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.wang@xxxxxxxxxx> --- 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 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ 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); } -- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
