linux-kernel - Re: [PATCH] firmware: arm_scmi: Avoid leak OF node on error

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Date:   Mon, 23 May 2022 14:27:28 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     cgel.zte@...il.com
Cc:     cristian.marussi@....com, linux-arm-kernel@...ts.infradead.org,
        Sudeep Holla <sudeep.holla@....com>,
        linux-kernel@...r.kernel.org, Minghao Chi <chi.minghao@....com.cn>,
        Zeal Robot <zealci@....com.cn>
Subject: Re: [PATCH] firmware: arm_scmi: Avoid leak OF node on error

On Mon, May 23, 2022 at 11:11:16AM +0000, cgel.zte@...il.com wrote:
> From: Minghao Chi <chi.minghao@....com.cn>
> 
> The OF node should be put before returning error in smc_chan_available(),
> otherwise node's refcount will be leaked.
> 
> Reported-by: Zeal Robot <zealci@....com.cn>
> Signed-off-by: Minghao Chi <chi.minghao@....com.cn>
> ---
>  drivers/firmware/arm_scmi/smc.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/firmware/arm_scmi/smc.c b/drivers/firmware/arm_scmi/smc.c
> index 745acfdd0b3d..43018be70edc 100644
> --- a/drivers/firmware/arm_scmi/smc.c
> +++ b/drivers/firmware/arm_scmi/smc.c
> @@ -55,10 +55,10 @@ static irqreturn_t smc_msg_done_isr(int irq, void *data)
>  static bool smc_chan_available(struct device *dev, int idx)
>  {
>  	struct device_node *np = of_parse_phandle(dev->of_node, "shmem", 0);
> +	of_node_put(np);

While this may work as of_node_put handles NULL as argument, what is the
point of unnecessary of_node_put(NULL) here ?

-- 
Regards,
Sudeep