From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jianchao Wang Subject: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating Date: Fri, 12 Jan 2018 11:42:22 +0800 Message-ID: <1515728542-3060-1-git-send-email-jianchao.w.wang@oracle.com> Cc: junxiao.bi-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org, netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: tariqt-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org Return-path: Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: netdev.vger.kernel.org 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 --- 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-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html