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From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Jerin Jacob <jerinjacobk@gmail.com>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.com>
Cc: ZY Qiu <quzeyao@gmail.com>, Thomas Monjalon <thomas@monjalon.net>,
	Andrew Rybchenko <arybchenko@solarflare.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"stephen@networkplumber.org" <stephen@networkplumber.org>,
	ZY Qiu <tgw_team@tencent.com>
Subject: Re: [dpdk-dev] [PATCH v3] rte_ethdev: safer memory access by calling Rx/Tx callback
Date: Thu, 1 Oct 2020 16:14:58 +0100
Message-ID: <290cc5e4-eed8-39ba-32ac-6290673ef4cf@intel.com> (raw)
In-Reply-To: <CALBAE1M9pv6r3MK=nCY-8Kr7DSEu+y+yK90i_v=C2V--p4kCjg@mail.gmail.com>

On 3/11/2020 12:26 PM, Jerin Jacob wrote:
> On Wed, Mar 11, 2020 at 5:52 PM Ananyev, Konstantin
> <konstantin.ananyev@intel.com> wrote:
>>
>>
>>
>>> -----Original Message-----
>>> From: ZY Qiu <quzeyao@gmail.com>
>>> Sent: Thursday, March 5, 2020 4:47 PM
>>> To: Thomas Monjalon <thomas@monjalon.net>; Yigit, Ferruh <ferruh.yigit@intel.com>; Andrew Rybchenko <arybchenko@solarflare.com>
>>> Cc: dev@dpdk.org; stephen@networkplumber.org; Ananyev, Konstantin <konstantin.ananyev@intel.com>; ZY Qiu
>>> <tgw_team@tencent.com>
>>> Subject: [PATCH v3] rte_ethdev: safer memory access by calling Rx/Tx callback
>>>
>>> When compiling with -O0,
>>> the compiler does not optimize two memory accesses into one.
>>> Leads to accessing a null pointer when queue post Rx burst callback
>>> removal while traffic is running.
>>>
>>> Signed-off-by: ZY Qiu <tgw_team@tencent.com>
>>> ---
>>>   lib/librte_ethdev/rte_ethdev.h | 9 +++++----
>>>   1 file changed, 5 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/lib/librte_ethdev/rte_ethdev.h b/lib/librte_ethdev/rte_ethdev.h
>>> index d1a593ad1..c46612e3e 100644
>>> --- a/lib/librte_ethdev/rte_ethdev.h
>>> +++ b/lib/librte_ethdev/rte_ethdev.h
>>> @@ -4388,10 +4388,10 @@ rte_eth_rx_burst(uint16_t port_id, uint16_t queue_id,
>>>                                     rx_pkts, nb_pkts);
>>>
>>>   #ifdef RTE_ETHDEV_RXTX_CALLBACKS
>>> -     if (unlikely(dev->post_rx_burst_cbs[queue_id] != NULL)) {
>>> -             struct rte_eth_rxtx_callback *cb =
>>> -                             dev->post_rx_burst_cbs[queue_id];
>>> +     struct rte_eth_rxtx_callback *volatile cb =
>>> +                     dev->post_rx_burst_cbs[queue_id];
> 
> I prefer to change to compiler_barrier() if it working as volatile may have a
> performance impact on fast-path code.
> 

Hi ZY Qiu,

Did you able to test with compiler barrier, is it solving your problem?

If there is no update on the issue, I will mark it as rejected.

Thanks,
ferruh


> 
>>>
>>> +     if (unlikely(cb != NULL)) {
>>>                do {
>>>                        nb_rx = cb->fn.rx(port_id, queue_id, rx_pkts, nb_rx,
>>>                                                nb_pkts, cb->param);
>>> @@ -4652,7 +4652,8 @@ rte_eth_tx_burst(uint16_t port_id, uint16_t queue_id,
>>>   #endif
>>>
>>>   #ifdef RTE_ETHDEV_RXTX_CALLBACKS
>>> -     struct rte_eth_rxtx_callback *cb = dev->pre_tx_burst_cbs[queue_id];
>>> +     struct rte_eth_rxtx_callback *volatile cb =
>>> +                     dev->pre_tx_burst_cbs[queue_id];
>>>
>>>        if (unlikely(cb != NULL)) {
>>>                do {
>>> --
>>
>> Acked-by: Konstantin Ananyev <konstantin.ananyev@intel.com>
>>
>>> 2.17.1
>>


      reply	other threads:[~2020-10-01 15:15 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-04 14:05 [dpdk-dev] [PATCH] rte_ethdev: fix unsafe memory access by calling RX callback Tencent TGW team
2020-03-04 14:16 ` Andrew Rybchenko
     [not found]   ` <61a6b7d5533643d692c40dc0ab1a2cdc@tencent.com>
2020-03-04 16:26     ` tgw_team(腾讯网关团队)
2020-03-04 16:15 ` Stephen Hemminger
2020-03-04 16:38   ` [dpdk-dev] [PATCH] rte_ethdev: fix unsafe memory access by calling RX callback.(Internet mail) tgw_team(腾讯网关团队)
2020-03-04 17:37     ` Stephen Hemminger
2020-03-04 17:44       ` [dpdk-dev] [PATCH] rte_ethdev: fix unsafe memory access by calling RX callback tgw_team(腾讯网关团队)
2020-03-04 17:33 ` [dpdk-dev] [PATCH v2] rte_ethdev: safer memory access by calling Rx callback ZY Qiu
2020-03-04 17:56   ` Stephen Hemminger
2020-03-04 18:31     ` tgw_team(腾讯网关团队)
2020-03-05  9:19   ` Bruce Richardson
2020-03-05 11:27     ` Ananyev, Konstantin
2020-03-05 14:23       ` tgw_team(腾讯网关团队)
2020-03-05 14:47       ` Liang, Ma
2020-03-05 15:19         ` Ananyev, Konstantin
2020-03-05 15:42           ` Liang, Ma
2020-03-05 16:47   ` [dpdk-dev] [PATCH v3] rte_ethdev: safer memory access by calling Rx/Tx callback ZY Qiu
2020-03-05 17:23     ` Jerin Jacob
2020-03-11 12:22     ` Ananyev, Konstantin
2020-03-11 12:26       ` Jerin Jacob
2020-10-01 15:14         ` Ferruh Yigit [this message]

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