Re: [dpdk-dev] [PATCH] ethdev: move sanity checks to non-debug paths

[Andrew Rybchenko <arybchenko@solarflare.com>]

On 23.07.2018 17:19, Ananyev, Konstantin wrote:
>> -----Original Message-----
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Matan Azrad
>> Sent: Monday, July 23, 2018 1:14 PM
>> To: Aaron Conole <aconole@redhat.com>
>> Cc: dev@dpdk.org; Yigit, Ferruh <ferruh.yigit@intel.com>; Marcelo Leitner <mleitner@redhat.com>; Shahaf Shuler
>> <shahafs@mellanox.com>; Ori Kam <orika@mellanox.com>; Thomas Monjalon <thomas@monjalon.net>
>> Subject: Re: [dpdk-dev] [PATCH] ethdev: move sanity checks to non-debug paths
>>
>>
>> Hi Aaron
>> From: Aaron Conole
>>> Sent: Monday, July 23, 2018 2:52 PM
>>> To: Matan Azrad <matan@mellanox.com>
>>> Cc: dev@dpdk.org; Ferruh Yigit <ferruh.yigit@intel.com>; Marcelo Leitner
>>> <mleitner@redhat.com>; Shahaf Shuler <shahafs@mellanox.com>; Ori Kam
>>> <orika@mellanox.com>; Thomas Monjalon <thomas@monjalon.net>
>>> Subject: Re: [dpdk-dev] [PATCH] ethdev: move sanity checks to non-debug paths
>>>
>>> Matan Azrad <matan@mellanox.com> writes:
>>>
>>>> Hi Aaron
>>>>
>>>> From: Aaron Conole
>>>>> These checks would have prevented a reported crash in the field.  If
>>>>> a user builds without ETHDEV_DEBUG, it should make their application
>>>>> more stable, not less.
>>>>>
>>>>> Many of these functions immediately dereference arrays based on the
>>>>> passed in values, so the sanity checks are quite important.
>>>>>
>>>> These functions are datapath functions.
>>>> Do you really want to add more 3 checks + calculations per each burst call?
>>>> Did you check the performance impact?
>>>> I think that performance numbers must be added for the discussion of this
>>> patch.
>>>
>>> I'll dig up performance numbers - but performance doesn't mean anything if
>>> the application isn't running any longer due to crash.
>> Yes, I understand your point, but think about that, if we are going to defend each user mistake it will cost a lot.
>> For example in Tx path, Adding checks for each mbuf pointer and mbuf data validity will be very expensive.
>>
>> I think the best way is to check the common user mistakes in DEBUG mode to help for application debugging and that's it.
> +1
> The problem is that user provided an invalid input parameters.
> Adding just extra checks inside data-path functions wouldn't solve it.
> Konstantin

+1, I agree with Matan and Konstantin
So, NACK

>>>>> The logs are left as DEBUG only.
>>>>>
>>>>> Cc: Marcelo Leitner <mleitner@redhat.com>
>>>>> Signed-off-by: Aaron Conole <aconole@redhat.com>
>>>>> ---
>>>>>   lib/librte_ethdev/rte_ethdev.h | 29 +++++++++++++----------------
>>>>>   1 file changed, 13 insertions(+), 16 deletions(-)
>>>>>
>>>>> diff --git a/lib/librte_ethdev/rte_ethdev.h
>>>>> b/lib/librte_ethdev/rte_ethdev.h index f5f593b31..bfd6a3406 100644
>>>>> --- a/lib/librte_ethdev/rte_ethdev.h
>>>>> +++ b/lib/librte_ethdev/rte_ethdev.h
>>>>> @@ -3805,15 +3805,16 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t
>>>>> queue_id,
>>>>>   	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
>>>>>   	uint16_t nb_rx;
>>>>>
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
>>>>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->rx_pkt_burst, 0);
>>>>>
>>>>>   	if (queue_id >= dev->data->nb_rx_queues) {
>>>>> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   		RTE_ETHDEV_LOG(ERR, "Invalid RX queue_id=%u\n",
>>> queue_id);
>>>>> +#endif
>>>>>   		return 0;
>>>>>   	}
>>>>> -#endif
>>>>> +
>>>>>   	nb_rx = (*dev->rx_pkt_burst)(dev->data->rx_queues[queue_id],
>>>>>   				     rx_pkts, nb_pkts);
>>>>>
>>>>> @@ -3928,14 +3929,12 @@ rte_eth_rx_descriptor_status(uint16_t
>>>>> port_id, uint16_t queue_id,
>>>>>   	struct rte_eth_dev *dev;
>>>>>   	void *rxq;
>>>>>
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); -#endif
>>>>>   	dev = &rte_eth_devices[port_id];
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>> +
>>>>>   	if (queue_id >= dev->data->nb_rx_queues)
>>>>>   		return -ENODEV;
>>>>> -#endif
>>>>> +
>>>>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->rx_descriptor_status, -
>>>>> ENOTSUP);
>>>>>   	rxq = dev->data->rx_queues[queue_id];
>>>>>
>>>>> @@ -3985,14 +3984,12 @@ static inline int
>>>>> rte_eth_tx_descriptor_status(uint16_t port_id,
>>>>>   	struct rte_eth_dev *dev;
>>>>>   	void *txq;
>>>>>
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, -ENODEV); -#endif
>>>>>   	dev = &rte_eth_devices[port_id];
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>> +
>>>>>   	if (queue_id >= dev->data->nb_tx_queues)
>>>>>   		return -ENODEV;
>>>>> -#endif
>>>>> +
>>>>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->tx_descriptor_status, -
>>>>> ENOTSUP);
>>>>>   	txq = dev->data->tx_queues[queue_id];
>>>>>
>>>>> @@ -4071,15 +4068,15 @@ rte_eth_tx_burst(uint16_t port_id, uint16_t
>>>>> queue_id,  {
>>>>>   	struct rte_eth_dev *dev = &rte_eth_devices[port_id];
>>>>>
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
>>>>>   	RTE_FUNC_PTR_OR_ERR_RET(*dev->tx_pkt_burst, 0);
>>>>>
>>>>>   	if (queue_id >= dev->data->nb_tx_queues) {
>>>>> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   		RTE_ETHDEV_LOG(ERR, "Invalid TX queue_id=%u\n",
>>> queue_id);
>>>>> +#endif
>>>>>   		return 0;
>>>>>   	}
>>>>> -#endif
>>>>>
>>>>>   #ifdef RTE_ETHDEV_RXTX_CALLBACKS
>>>>>   	struct rte_eth_rxtx_callback *cb = dev->pre_tx_burst_cbs[queue_id];
>>>>> @@ -4160,23 +4157,23 @@ rte_eth_tx_prepare(uint16_t port_id, uint16_t
>>>>> queue_id,  {
>>>>>   	struct rte_eth_dev *dev;
>>>>>
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   	if (!rte_eth_dev_is_valid_port(port_id)) {
>>>>> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   		RTE_ETHDEV_LOG(ERR, "Invalid TX port_id=%u\n", port_id);
>>>>> +#endif
>>>>>   		rte_errno = -EINVAL;
>>>>>   		return 0;
>>>>>   	}
>>>>> -#endif
>>>>>
>>>>>   	dev = &rte_eth_devices[port_id];
>>>>>
>>>>> -#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   	if (queue_id >= dev->data->nb_tx_queues) {
>>>>> +#ifdef RTE_LIBRTE_ETHDEV_DEBUG
>>>>>   		RTE_ETHDEV_LOG(ERR, "Invalid TX queue_id=%u\n",
>>> queue_id);
>>>>> +#endif
>>>>>   		rte_errno = -EINVAL;
>>>>>   		return 0;
>>>>>   	}
>>>>> -#endif
>>>>>
>>>>>   	if (!dev->tx_pkt_prepare)
>>>>>   		return nb_pkts;
>>>>> --
>>>>> 2.14.3