From: David Miller <davem@davemloft.net>
To: wenxiong@linux.vnet.ibm.com
Cc: ariel.elior@qlogic.com, netdev@vger.kernel.org, miltonm@bga.com
Subject: Re: [PATCH V2 2/2] bnx2x: Fix kernel crash and data miscompare after EEH recovery
Date: Sun, 01 Jun 2014 19:26:13 -0700 (PDT) [thread overview]
Message-ID: <20140601.192613.1152234930286860733.davem@davemloft.net> (raw)
In-Reply-To: <20140528155722.361752083@linux.vnet.ibm.com>
From: wenxiong@linux.vnet.ibm.com
Date: Wed, 28 May 2014 10:56:43 -0500
> A rmb() is required to ensure that the CQE is not read before it
> is written by the adapter DMA. PCI ordering rules will make sure
> the other fields are written before the marker at the end of struct
> eth_fast_path_rx_cqe but without rmb() a weakly ordered processor can
> process stale data.
>
> Without the barrier we have observed various crashes including
> bnx2x_tpa_start being called on queues not stopped (resulting in message
> start of bin not in stop) and NULL pointer exceptions from bnx2x_rx_int.
>
> Signed-off-by: Milton Miller <miltonm@bga.com>
> Signed-off-by: Wen Xiong <wenxiong@linux.vnet.ibm.com>
> ---
> drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c | 12 ++++++++++++
> 1 file changed, 12 insertions(+)
>
> Index: b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c
> ===================================================================
> --- a/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c 2014-05-23 10:34:21.000000000 -0500
> +++ b/drivers/net/ethernet/broadcom/bnx2x/bnx2x_cmn.c 2014-05-28 10:54:26.627766086 -0500
> @@ -906,6 +906,18 @@ static int bnx2x_rx_int(struct bnx2x_fas
> bd_prod = RX_BD(bd_prod);
> bd_cons = RX_BD(bd_cons);
>
> + /* A rmb() is required to ensure that the CQE is not read
> + * before it is written by the adapter DMA. PCI ordering
> + * rules will make sure the other fields are written before
> + * the marker at the end of struct eth_fast_path_rx_cqe
> + * but without rmb() a weakly ordered processor can process
> + * stale data. Without the barrier TPA state-machine might
> + * enter inconsistent state and kernel stack might be
> + * provided with incorrect packet description - these lead
> + * to various kernel crashed.
> + */
Missing a space before the final "*/", this is not formatted correctly.
Please fix this and resubmit the whole series.
next prev parent reply other threads:[~2014-06-02 2:26 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-28 15:56 [PATCH V2 0/2] Adapter not recovery from EEH error injection wenxiong
2014-05-28 15:56 ` [PATCH V2 1/2] bnx2x: " wenxiong
2014-05-30 12:32 ` Dmitry Kravkov
2014-05-28 15:56 ` [PATCH V2 2/2] bnx2x: Fix kernel crash and data miscompare after EEH recovery wenxiong
2014-05-28 19:23 ` Dmitry Kravkov
2014-05-29 14:50 ` wenxiong
2014-06-02 2:26 ` David Miller [this message]
[not found] <87B4DDAD5EAFA041BDC28F314593782D0174F4A8@avmb3.qlogic.org>
2014-06-03 19:14 ` wenxiong
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