Subject: Re: i40e: crash on NMI by continuous module reload

From: nick <[email-masked]>
Date: Fri, 27 Feb 2015 09:44:24 -0500

On 2015-02-27 09:16 AM, Stefan Assmann wrote:
> On 27.02.2015 15:02, nick wrote:
> 
> [...]
> 
>>>     i40e: Fix a bug where Rx would stop after some time
>>> [...]
>>> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
>>> index f7464e8..ff6d94d 100644
>>> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
>>> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
>>> [...]
>>> @@ -9169,6 +9178,13 @@ static int i40e_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
>>>  	if (err)
>>>  		dev_info(&pf->pdev->dev, "set phy mask fail, aq_err %d\n", err);
>>>
>>> +	msleep(75);
>>> +	err = i40e_aq_set_link_restart_an(&pf->hw, true, NULL);
>>> +	if (err) {
>>> +		dev_info(&pf->pdev->dev, "link restart failed, aq_err=%d\n",
>>> +			 pf->hw.aq.asq_last_status);
>>> +	}
>>> +
>>>  	/* The main driver is (mostly) up and happy. We need to set this state
>>>  	 * before setting up the misc vector or we get a race and the vector
>>>  	 * ends up disabled forever.
>>>
>>> With this hunk removed the driver successfully unloaded/reloaded a
>>> couple of hundred times. Would it be safe to just remove this hunk?
>>> I haven't seen any negative effects by removing this yet.
>>>
>>>   Stefan
>>>
>> Stefan,
>> I wouldn't remove them yet as this does look like a valid idea to check to see if the link is 
>> restarting successfully. On the other hand can you try removing the msleep line as this one is
>> most likely causing the issue due to sleeping for some long in a probe function is generally a
>> bad idea.
>> Thanks,
>> Nick
> 
> Thanks Nick for the quick reply. I tested removing the msleep but that
> didn't make a difference. You actually need to remove the complete hunk
> to get a stable driver reload.
> 
>   Stefan
> 
Stefan,
Basically there are a few things that could be going wrong
1. You are getting a error return for the function,i40e_aq_set_link_restart_an
2. You are trying to re able the device again when not needed
3. You are sending a NULL value to a field for command arguments that takes a 0 and not NULL
to take no arguments
Nick 

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