Subject: Re: [PATCH] rpmsg: glink: Avoid infinite loop on intent for missing
 channel
To:     Bjorn Andersson <quic_bjorande@quicinc.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Mathieu Poirier <mathieu.poirier@linaro.org>
CC:     Sricharan Ramabadhran <quic_srichara@quicinc.com>,
        Arun Kumar Neelakantam <quic_aneelaka@quicinc.com>,
        <linux-arm-msm@vger.kernel.org>,
        <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <quic_clew@quicinc.com>
References: <20230109223801.1706213-1-quic_bjorande@quicinc.com>
From:   Chris Lew <quic_clew@quicinc.com>
Message-ID: <393b7d5f-b565-6287-bbab-3bf51cc981f0@quicinc.com>
Date:   Tue, 14 Feb 2023 14:55:02 -0800
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:78.0) Gecko/20100101
 Thunderbird/78.14.0
MIME-Version: 1.0
In-Reply-To: <20230109223801.1706213-1-quic_bjorande@quicinc.com>
Content-Type: text/plain; charset="utf-8"; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

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@quicinc.com>
> ---
>   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));
>   }
>   
>