From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jianchao Wang <jianchao.w.wang@oracle.com>
Cc: tariqt@mellanox.com, junxiao.bi@oracle.com,
netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
linux-kernel@vger.kernel.org,
Saeed Mahameed <saeedm@mellanox.com>
Subject: Re: [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating
Date: Fri, 12 Jan 2018 09:32:47 -0700 [thread overview]
Message-ID: <20180112163247.GB15974@ziepe.ca> (raw)
In-Reply-To: <1515728542-3060-1-git-send-email-jianchao.w.wang@oracle.com>
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.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
> +++ 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
next prev parent reply other threads:[~2018-01-12 16:32 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-12 3:42 [PATCH] net/mlx4_en: ensure rx_desc updating reaches HW before prod db updating Jianchao Wang
2018-01-12 16:32 ` Jason Gunthorpe [this message]
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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