Re: [PATCH] rpmsg: glink: Avoid dereferencing NULL channel

[Mathieu Poirier <mathieu.poirier@linaro.org>]

On Mon, Jul 17, 2023 at 09:55:38AM -0700, Bjorn Andersson wrote:
> The newly introduced signal command handler checks for non-existing
> channel and print an error message, but then continues on to dereference
> that same channel.
> 
> Instead abort the handler when no channel is found.
> 
> Fixes: a2b73aa512a4 ("rpmsg: glink: Add support to handle signals command")
> Reported-by: kernel test robot <lkp@intel.com>
> Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> Closes: https://lore.kernel.org/r/202307160800.sb7gMnL6-lkp@intel.com/
> Signed-off-by: Bjorn Andersson <quic_bjorande@quicinc.com>
> ---
>  drivers/rpmsg/qcom_glink_native.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/rpmsg/qcom_glink_native.c b/drivers/rpmsg/qcom_glink_native.c
> index e10c05ed21bb..82d460ff4777 100644
> --- a/drivers/rpmsg/qcom_glink_native.c
> +++ b/drivers/rpmsg/qcom_glink_native.c
> @@ -1070,8 +1070,10 @@ static void qcom_glink_handle_signals(struct qcom_glink *glink,
>  	spin_lock_irqsave(&glink->idr_lock, flags);
>  	channel = idr_find(&glink->rcids, rcid);
>  	spin_unlock_irqrestore(&glink->idr_lock, flags);
> -	if (!channel)
> +	if (!channel) {
>  		dev_err(glink->dev, "signal for non-existing channel\n");
> +		return;
> +	}

I have applied this patch.

Thanks,
Mathieu

>  
>  	enable = sigs & NATIVE_DSR_SIG || sigs & NATIVE_CTS_SIG;
>  
> -- 
> 2.25.1
>