Re: [dpdk-stable] [dpdk-dev] [PATCH v5] ethdev: fix DCB set failure

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 5/18/2020 3:57 PM, Matan Azrad wrote:
> 
> Hi
> 
>  From: Andrew Rybchenko
>> CC net/nfp maintainer
>>
>> On 5/13/20 8:16 PM, Ting Xu wrote:
>>> When rte_eth_dev_rss_hash_conf_get() is called, if the variable
>>> rss_conf is not initialized, the pointer member variable rss_key may
>>> have a random address, which leads to an error in the following
>>> processing. This patch initialized the variable rss_conf to avoid this
>>> situation.
>>>
>>> Fixes: 16321de09396 ("ethdev: allow to get RSS hash functions and
>>> key")
>>> Cc: stable@dpdk.org
>>>
>>> Signed-off-by: Ting Xu <ting.xu@intel.com>
>>>
>>> ---
>>> v4->v5: modify commit log
>>> V3->v4: fix build failure
>>> v2->v3: move memset to rte_eth_dev_rss_hash_conf_get from testpmd
>>> v1->v2: modify commit log, move memset to else leg
>>> ---
>>>  lib/librte_ethdev/rte_ethdev.c | 1 +
>>>  1 file changed, 1 insertion(+)
>>>
>>> diff --git a/lib/librte_ethdev/rte_ethdev.c
>>> b/lib/librte_ethdev/rte_ethdev.c index 8e10a6fc3..b20c6bb2d 100644
>>> --- a/lib/librte_ethdev/rte_ethdev.c
>>> +++ b/lib/librte_ethdev/rte_ethdev.c
>>> @@ -3552,6 +3552,7 @@ rte_eth_dev_rss_hash_conf_get(uint16_t
>> port_id,
>>>  	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV);
>>>  	dev = &rte_eth_devices[port_id];
>>>  	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rss_hash_conf_get,
>> -ENOTSUP);
>>> +	memset(rss_conf, 0, sizeof(*rss_conf));
>>>  	return eth_err(port_id, (*dev->dev_ops->rss_hash_conf_get)(dev,
>>>  								   rss_conf));
>>>  }
>>>
>>
>> The patch breaks getting of RSS key since it resets rss_conf->rss_key to
>> NULL, but all drivers treat it as a  pointer to buffer to copy RSS key to.
>> Almost all driver just skip RSS key copy if the pointer is NULL.
>>
>> I think it should be removed from next-net or improved to reset rss_hf only
>> since rss_key_len may be treated as a size of rss_key buffer. The API is not
>> clear at the place.
>>
>> It looks like net/nfp is the only driver which does not check that that pointer
>> is not NULL before coping key to it.
> 
> 
> +1
> 
> Looks like this breaks also Testpmd  "show port 0 rss-hash key" command.
> 

Hi Matan, it is clearly wrong, I will drop it.