From: "jianchao.wang" <jianchao.w.wang@oracle.com>
To: Tariq Toukan <tariqt@mellanox.com>,
Eric Dumazet <eric.dumazet@gmail.com>,
Jason Gunthorpe <jgg@ziepe.ca>
Cc: 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, 19 Jan 2018 23:16:09 +0800 [thread overview]
Message-ID: <53b1ac4d-a294-eb98-149e-65d7954243da@oracle.com> (raw)
In-Reply-To: <fea0aa1c-b68e-9485-3826-2dfad7824911@oracle.com>
Hi Tariq
Very sad that the crash was reproduced again after applied the patch.
--- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c
@@ -252,6 +252,7 @@ static inline bool mlx4_en_is_ring_empty(struct mlx4_en_rx_ring *ring)
static inline void mlx4_en_update_rx_prod_db(struct mlx4_en_rx_ring *ring)
{
+ dma_wmb();
*ring->wqres.db.db = cpu_to_be32(ring->prod & 0xffff);
}
I analyzed the kdump, it should be a memory corruption.
Thanks
Jianchao
On 01/15/2018 01:50 PM, jianchao.wang wrote:
> Hi Tariq
>
> Thanks for your kindly response.
>
> On 01/14/2018 05:47 PM, Tariq Toukan wrote:
>> Thanks Jianchao for your patch.
>>
>> And Thank you guys for your reviews, much appreciated.
>> I was off-work on Friday and Saturday.
>>
>> On 14/01/2018 4:40 AM, jianchao.wang wrote:
>>> Dear all
>>>
>>> Thanks for the kindly response and reviewing. That's really appreciated.
>>>
>>> On 01/13/2018 12:46 AM, Eric Dumazet wrote:
>>>>> Does this need to be dma_wmb(), and should it be in
>>>>> mlx4_en_update_rx_prod_db ?
>>>>>
>>>> +1 on dma_wmb()
>>>>
>>>> On what architecture bug was observed ?
>>> This issue was observed on x86-64.
>>> And I will send a new patch, in which replace wmb() with dma_wmb(), to customer
>>> to confirm.
>>
>> +1 on dma_wmb, let us know once customer confirms.
>> Please place it within mlx4_en_update_rx_prod_db as suggested.
> Yes, I have recommended it to customer.
> Once I get the result, I will share it here.
>> All other calls to mlx4_en_update_rx_prod_db are in control/slow path so I prefer being on the safe side, and care less about bulking the barrier.
>>
>> Thanks,
>> Tariq
>>
>
next prev parent reply other threads:[~2018-01-19 15:19 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
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 [this message]
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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