Re: [PATCH] Revert "can: dev: __can_get_echo_skb(): print error message, if trying to echo non existing skb"

From: Manfred Schlaegl
Date: Mon Jan 07 2019 - 03:51:08 EST


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ManfredÂSchlaeglÂ|ÂLeitung Entwicklung LinzÂ

GINZINGER ELECTRONIC SYSTEMS GMBH

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On 04.01.19 16:23, Marc Kleine-Budde wrote:
> On 12/19/18 7:39 PM, Manfred Schlaegl wrote:
>> This reverts commit 7da11ba5c5066dadc2e96835a6233d56d7b7764a.
>>
>> After introduction of this change we encountered following new error
>> message on various i.MX plattforms (flexcan)
>> flexcan 53fc8000.can can0: __can_get_echo_skb: BUG! Trying to echo non
>> existing skb: can_priv::echo_skb[0]
>
> Doh! I should have tested more extensive. Sorry.
>
>> The introduction of the message was a mistake because
>> priv->echo_skb[idx] = NULL is a perfectly valid in following case:
>> If CAN_RAW_LOOPBACK is disabled (setsockopt) in applications, the
>> pkt_type of the tx skb's given to can_put_echo_skb is set to
>> PACKET_LOOPBACK. In this case can_put_echo_skb will not set
>> priv->echo_skb[idx]. It is therefore kept NULL.
>>
>> (As additional argument for revert: The order of check and usage of idx
>> was changed. idx is used to access an array element before checking it's
>> boundaries)
>>
>> Signed-off-by: Manfred Schlaegl <manfred.schlaegl@xxxxxxxxxxxxx>
>
> Applied to linux-can.

Great, thanks!

>
> Tnx,
> Marc
>




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