From: Jianchao Wang <jianchao.w.wang@oracle.com>
To: tariqt@mellanox.com
Cc: junxiao.bi@oracle.com, netdev@vger.kernel.org,
linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating
Date: Fri, 12 Jan 2018 11:42:22 +0800 [thread overview]
Message-ID: <1515728542-3060-1-git-send-email-jianchao.w.wang@oracle.com> (raw)
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@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
next reply other threads:[~2018-01-12 3:42 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 3:42 Jianchao Wang [this message]
2018-01-12 16:32 ` [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating Jason Gunthorpe
2018-01-12 16:46 ` Eric Dumazet
2018-01-12 19:53 ` Saeed Mahameed
2018-01-12 20:16 ` Eric Dumazet
2018-01-12 21:01 ` Saeed Mahameed
2018-01-12 21:21 ` Eric Dumazet
2018-01-13 19:15 ` Jason Gunthorpe
2018-01-14 2:40 ` jianchao.wang
2018-01-14 9:47 ` Tariq Toukan
2018-01-15 5:50 ` jianchao.wang
2018-01-19 15:16 ` jianchao.wang
2018-01-19 15:49 ` Eric Dumazet
2018-01-21 9:31 ` Tariq Toukan
2018-01-21 16:24 ` Tariq Toukan
2018-01-21 16:43 ` Eric Dumazet
2018-01-22 2:40 ` jianchao.wang
2018-01-22 15:47 ` Jason Gunthorpe
2018-01-23 3:25 ` jianchao.wang
2018-01-22 2:12 ` jianchao.wang
2018-01-25 3:27 ` jianchao.wang
2018-01-25 3:55 ` Eric Dumazet
2018-01-25 6:25 ` jianchao.wang
2018-01-25 9:54 ` Tariq Toukan
2018-01-27 12:41 ` jianchao.wang
[not found] ` <d9883261-e93e-400a-757c-3a81d8b6aca1@mellanox.com>
2019-01-02 1:43 ` jianchao.wang
2018-01-21 20:40 ` Jason Gunthorpe
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