linux-kernel - Re: [PATCH] can: dev: clean up CAN ctrlmode when close CAN device

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Wed, 10 Apr 2019 09:19:02 +0200
From:   Marc Kleine-Budde <mkl@...gutronix.de>
To:     Joakim Zhang <qiangqing.zhang@....com>,
        "wg@...ndegger.com" <wg@...ndegger.com>,
        "davem@...emloft.net" <davem@...emloft.net>
Cc:     dl-linux-imx <linux-imx@....com>,
        "linux-can@...r.kernel.org" <linux-can@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] can: dev: clean up CAN ctrlmode when close CAN device

On 4/10/19 8:27 AM, Joakim Zhang wrote:
> CAN driver always writes registers according to "ctrlmode", and now CAN
> framework will keep CAN ctrlmode after device closed.
> 
> e.g. with following sequences:
> 1)ip link set can0 type can bitrate 1000000 loopback on
> 2)ip link set can0 up
> 3)ip link set can0 down
> 4)ip link set can0 type can bitrate 1000000
> 5)ip link set can0 up
> 
> After this sequence, we may want to test loopback for the first time and
> not to test loopback second time. However, CAN device still keep
> "ctrlmode" as loopback on.

Then you should configure loopback off in userspace.

> This patch intends to clean up CAN ctrlmode when close CAN device. We
> can set which ctrlmode we need when open CAN device again.

Consider a CANFD device, where CANFD has been enabled. It will feel very
weird if the interface looses the CANFD property by just a ifdown; ifup.

> 
> Signed-off-by: Joakim Zhang <qiangqing.zhang@....com>
> ---
>  drivers/net/can/dev.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
> index c05e4d50d43d..4f69a8f16ba3 100644
> --- a/drivers/net/can/dev.c
> +++ b/drivers/net/can/dev.c
> @@ -870,6 +870,7 @@ void close_candev(struct net_device *dev)
>  	struct can_priv *priv = netdev_priv(dev);
>  
>  	cancel_delayed_work_sync(&priv->restart_work);
> +	priv->ctrlmode = 0;
>  	can_flush_echo_skb(dev);
>  }
>  EXPORT_SYMBOL_GPL(close_candev);
> 

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   |



Download attachment "signature.asc" of type "application/pgp-signature" (489 bytes)