netdev - Re: [net 03/11] can: isotp: TX-path: ensure that CAN frame flags are initialized

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Message-ID: <bd9fc82e-d67b-34c8-fb74-8977b8825078@hartkopp.net>
Date:   Thu, 18 Mar 2021 11:11:42 +0100
From:   Oliver Hartkopp <socketcan@...tkopp.net>
To:     Marc Kleine-Budde <mkl@...gutronix.de>, netdev@...r.kernel.org
Cc:     davem@...emloft.net, kuba@...nel.org, linux-can@...r.kernel.org,
        kernel@...gutronix.de
Subject: Re: [net 03/11] can: isotp: TX-path: ensure that CAN frame flags are
 initialized

Hello Marc,

I obviously missed these patches - but they are fine. Thanks!

After checking your patch I was going after this missing initialization 
and detected that the outgoing CAN frame skbs from isotp.c were not 
properly zero initialized - so I sent a patch for it some minutes ago:

https://lore.kernel.org/linux-can/20210318100233.1693-1-socketcan@hartkopp.net/T/#u

In fact I had

 > CONFIG_INIT_ON_ALLOC_DEFAULT_ON=y
 > CONFIG_INIT_ON_FREE_DEFAULT_ON=y

in my local kernel config therefore I was not able to see it on my own :-/

Best,
Oliver

On 16.03.21 09:20, Marc Kleine-Budde wrote:
> The previous patch ensures that the TX flags (struct
> can_isotp_ll_options::tx_flags) are 0 for classic CAN frames or a user
> configured value for CAN-FD frames.
> 
> This patch sets the CAN frames flags unconditionally to the ISO-TP TX
> flags, so that they are initialized to a proper value. Otherwise when
> running "candump -x" on a classical CAN ISO-TP stream shows wrongly
> set "B" and "E" flags.
> 
> | $ candump any,0:0,#FFFFFFFF -extA
> | [...]
> | can0  TX B E  713   [8]  2B 0A 0B 0C 0D 0E 0F 00
> | can0  TX B E  713   [8]  2C 01 02 03 04 05 06 07
> | can0  TX B E  713   [8]  2D 08 09 0A 0B 0C 0D 0E
> | can0  TX B E  713   [8]  2E 0F 00 01 02 03 04 05
> 
> Fixes: e057dd3fc20f ("can: add ISO 15765-2:2016 transport protocol")
> Link: https://lore.kernel.org/r/20210218215434.1708249-2-mkl@pengutronix.de
> Cc: Oliver Hartkopp <socketcan@...tkopp.net>
> Signed-off-by: Marc Kleine-Budde <mkl@...gutronix.de>
> ---
>   net/can/isotp.c | 9 +++------
>   1 file changed, 3 insertions(+), 6 deletions(-)
> 
> diff --git a/net/can/isotp.c b/net/can/isotp.c
> index e32d446c121e..430976485d95 100644
> --- a/net/can/isotp.c
> +++ b/net/can/isotp.c
> @@ -215,8 +215,7 @@ static int isotp_send_fc(struct sock *sk, int ae, u8 flowstatus)
>   	if (ae)
>   		ncf->data[0] = so->opt.ext_address;
>   
> -	if (so->ll.mtu == CANFD_MTU)
> -		ncf->flags = so->ll.tx_flags;
> +	ncf->flags = so->ll.tx_flags;
>   
>   	can_send_ret = can_send(nskb, 1);
>   	if (can_send_ret)
> @@ -790,8 +789,7 @@ static enum hrtimer_restart isotp_tx_timer_handler(struct hrtimer *hrtimer)
>   		so->tx.sn %= 16;
>   		so->tx.bs++;
>   
> -		if (so->ll.mtu == CANFD_MTU)
> -			cf->flags = so->ll.tx_flags;
> +		cf->flags = so->ll.tx_flags;
>   
>   		skb->dev = dev;
>   		can_skb_set_owner(skb, sk);
> @@ -939,8 +937,7 @@ static int isotp_sendmsg(struct socket *sock, struct msghdr *msg, size_t size)
>   	}
>   
>   	/* send the first or only CAN frame */
> -	if (so->ll.mtu == CANFD_MTU)
> -		cf->flags = so->ll.tx_flags;
> +	cf->flags = so->ll.tx_flags;
>   
>   	skb->dev = dev;
>   	skb->sk = sk;
>