From: Marc Kleine-Budde <mkl@pengutronix.de>
To: Srinivas Neeli <sneeli@xilinx.com>,
"wg@grandegger.com" <wg@grandegger.com>
Cc: Srinivas Goud <sgoud@xilinx.com>,
Naga Sureshkumar Relli <nagasure@xilinx.com>,
Appana Durga Kedareswara Rao <appanad@xilinx.com>,
"linux-can@vger.kernel.org" <linux-can@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: Query on possible bug in the can_create_echo_skb() API
Date: Wed, 28 Aug 2019 14:15:51 +0200 [thread overview]
Message-ID: <3a8c557f-adb5-144d-00f1-1b1c608129dc@pengutronix.de> (raw)
In-Reply-To: <BYAPR02MB546403642B2233DDD5C456C4AFA30@BYAPR02MB5464.namprd02.prod.outlook.com>
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On 8/28/19 1:02 PM, Srinivas Neeli wrote:
> Case 1:
> can_put_echo_skb(); -> skb = can_create_echo_skb(skb); -> return skb;
>
> In can_create_echo_skb() not using the shared_skb, so we are returning the old skb.
> Storing the return value in "skb". But it's a pointer, for storing that need double pointer.
> Instead of double-pointer using a single pointer. In this scenario it's ok , we are returning the same SKB.
>
> Case 2:
> can_put_echo_skb(skb, ndev, priv->tx_head % priv->tx_max); -> skb = can_create_echo_skb(skb); -> can_skb_set_owner(nskb, skb->sk); - Returning nskb;
>
> shared_skb scenario:
> In share-skb case “can_create_echo_skb(skb);” returning "new skb". For storing new skb need a double pointer.
>
> Providing an example for overcoming above issue.
> Example:
> can_put_echo_skb(struct sk_buff **skb,struct net_device *dev,unsigned int idx);
Now I get what you mean.
> If you ok with this change, I will send a patch.
I think the can_put_echo_skb() API needs clarification. The driver is
not allowed to touch the skb any more after can_put_echo_skb(). We
should review the driver for this.
thanks,
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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prev parent reply other threads:[~2019-08-28 12:16 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <BYAPR02MB5464DC9DA2D38AF1100A5A8FAFAA0@BYAPR02MB5464.namprd02.prod.outlook.com>
[not found] ` <6bd3a657-dd8a-03a5-1e7c-bac532008f6e@pengutronix.de>
2019-08-28 11:02 ` Query on possible bug in the can_create_echo_skb() API Srinivas Neeli
2019-08-28 12:15 ` Marc Kleine-Budde [this message]
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