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
--- 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
