Re: [PATCH] rpmsg: glink: Avoid infinite loop on intent for missing channel

[Chris Lew]

On 1/9/2023 2:38 PM, Bjorn Andersson wrote:
> In the event that an intent advertisement arrives on an unknown channel
> the fifo is not advanced, resulting in the same message being handled
> over and over.
>
> Fixes: dacbb35e930f ("rpmsg: glink: Receive and store the remote intent buffers")
> Signed-off-by: Bjorn Andersson <quic_bjorande@xxxxxxxxxxx>
> ---
>   drivers/rpmsg/qcom_glink_native.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index f36740cb6866..7b1320b1579e 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -946,12 +946,12 @@ static void qcom_glink_handle_intent(struct qcom_glink *glink,
>   	spin_unlock_irqrestore(&glink->idr_lock, flags);
>   	if (!channel) {
>   		dev_err(glink->dev, "intents for non-existing channel\n");
> -		return;
> +		goto advance_rx;
>   	}
>   
>   	msg = kmalloc(msglen, GFP_ATOMIC);
>   	if (!msg)
> -		return;
> +		goto advance_rx;


Should we be dropping the packet for this case? If we try again later 
more memory might be available to handle the command.

>   
>   	qcom_glink_rx_peak(glink, msg, 0, msglen);
>   
> @@ -973,6 +973,7 @@ static void qcom_glink_handle_intent(struct qcom_glink *glink,
>   	}
>   
>   	kfree(msg);
> +advance_rx:
>   	qcom_glink_rx_advance(glink, ALIGN(msglen, 8));
>   }
>