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From: Konstantin Ananyev <konstantin.ananyev@huawei.com>
To: Ashok Kaladi <ashok.k.kaladi@intel.com>,
	"jerinj@marvell.com" <jerinj@marvell.com>,
	"thomas@monjalon.net" <thomas@monjalon.net>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	"s.v.naga.harish.k@intel.com" <s.v.naga.harish.k@intel.com>,
	"erik.g.carrillo@intel.com" <erik.g.carrillo@intel.com>,
	"abhinandan.gujjar@intel.com" <abhinandan.gujjar@intel.com>,
	"stable@dpdk.org" <stable@dpdk.org>
Subject: RE: [PATCH 2/2] ethdev: fix race condition in fast-path ops setup
Date: Mon, 20 Feb 2023 09:44:06 +0000	[thread overview]
Message-ID: <5fbc2c46c9d94532a0e55656acb4d5a8@huawei.com> (raw)
In-Reply-To: <20230220060839.1267349-2-ashok.k.kaladi@intel.com>



> If ethdev enqueue or dequeue function is called during
> eth_dev_fp_ops_setup(), it may get pre-empted after setting
> the function pointers, but before setting the pointer to port data.
> In this case the newly registered enqueue/dequeue function will use
> dummy port data and end up in seg fault.
> 
> This patch moves the updation of each data pointers before updating
> corresponding function pointers.

First, such re-ordering wouldn't really fix that race condition.
Second, eth_dev_fp_ops_setup() supposed to be called only by dev/queue start/stop functions.
With current DPDK design it is not allowed to simultaneously call dev start/stop
and  data-path RX/TX functions and it is user responsibility to ensure that.
In other words - it is user responsibility to ensure that such race condition would 
not happen.
So, NACK.

> 
> Fixes: c87d435a4d79 ("ethdev: copy fast-path API into separate structure")
> Cc: stable@dpdk.org
> 
> Signed-off-by: Ashok Kaladi <ashok.k.kaladi@intel.com>
> 
> diff --git a/lib/ethdev/ethdev_private.c b/lib/ethdev/ethdev_private.c
> index 48090c879a..a0232c669f 100644
> --- a/lib/ethdev/ethdev_private.c
> +++ b/lib/ethdev/ethdev_private.c
> @@ -270,17 +270,17 @@ void
>  eth_dev_fp_ops_setup(struct rte_eth_fp_ops *fpo,
>  		const struct rte_eth_dev *dev)
>  {
> +	fpo->rxq.data = dev->data->rx_queues;
>  	fpo->rx_pkt_burst = dev->rx_pkt_burst;
> +	fpo->txq.data = dev->data->tx_queues;
>  	fpo->tx_pkt_burst = dev->tx_pkt_burst;
>  	fpo->tx_pkt_prepare = dev->tx_pkt_prepare;
>  	fpo->rx_queue_count = dev->rx_queue_count;
>  	fpo->rx_descriptor_status = dev->rx_descriptor_status;
>  	fpo->tx_descriptor_status = dev->tx_descriptor_status;
> 
> -	fpo->rxq.data = dev->data->rx_queues;
>  	fpo->rxq.clbk = (void **)(uintptr_t)dev->post_rx_burst_cbs;
> 
> -	fpo->txq.data = dev->data->tx_queues;
>  	fpo->txq.clbk = (void **)(uintptr_t)dev->pre_tx_burst_cbs;
>  }
> 
> --
> 2.25.1


  parent reply	other threads:[~2023-02-20  9:44 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-20  6:08 [PATCH 1/2] eventdev: fix race condition in fast-path set function Ashok Kaladi
2023-02-20  6:08 ` [PATCH 2/2] ethdev: fix race condition in fast-path ops setup Ashok Kaladi
2023-02-20  6:57   ` fengchengwen
2023-02-21  7:24     ` Ruifeng Wang
2023-02-21 17:00       ` Stephen Hemminger
2023-02-22  1:07         ` fengchengwen
2023-02-22  9:41           ` Ruifeng Wang
2023-02-22 10:41           ` Konstantin Ananyev
2023-02-22 22:48             ` Honnappa Nagarahalli
2023-02-23  1:15               ` Stephen Hemminger
2023-02-23  4:47                 ` Honnappa Nagarahalli
2023-02-23  4:40             ` Honnappa Nagarahalli
2023-02-23  8:23               ` fengchengwen
2023-02-23 13:31                 ` Konstantin Ananyev
2023-02-25  1:32                   ` fengchengwen
2023-02-26 17:22                     ` Konstantin Ananyev
2023-02-27  2:56                       ` fengchengwen
2023-02-27 19:08                         ` Konstantin Ananyev
2023-03-03 17:19                       ` Ferruh Yigit
2023-03-06  1:57                         ` fengchengwen
2023-03-06  6:13                         ` Ruifeng Wang
2023-03-06 10:32                           ` Konstantin Ananyev
2023-03-06 11:17                             ` Ajit Khaparde
2023-03-06 11:57                             ` Ferruh Yigit
2023-03-06 12:36                               ` Konstantin Ananyev
2023-02-28 23:57                   ` Honnappa Nagarahalli
2023-02-20  7:01   ` fengchengwen
2023-02-20  9:44   ` Konstantin Ananyev [this message]
2023-03-03 16:49   ` Ferruh Yigit

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