linux-kernel - Re: [PATCH 2/4] ARM: mvebu: fix a leaked reference by adding missing of_node

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Date:   Sun, 21 Apr 2019 19:24:17 +0200
From:   Gregory CLEMENT <gregory.clement@...tlin.com>
To:     Wen Yang <wen.yang99@....com.cn>, linux-kernel@...r.kernel.org
Cc:     wang.yi59@....com.cn, Wen Yang <wen.yang99@....com.cn>,
        Jason Cooper <jason@...edaemon.net>,
        Andrew Lunn <andrew@...n.ch>,
        Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
        Russell King <linux@...linux.org.uk>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 2/4] ARM: mvebu: fix a leaked reference by adding missing of_node_put

Hi Wen Yang,

> The call to of_get_next_child returns a node pointer with refcount
> incremented thus it must be explicitly decremented after the last
> usage.
>
> Detected by coccinelle with the following warnings:
> ./arch/arm/mach-mvebu/pm-board.c:135:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 88, but without a corresponding object release within this functio
>
> Signed-off-by: Wen Yang <wen.yang99@....com.cn>
> Cc: Jason Cooper <jason@...edaemon.net>
> Cc: Andrew Lunn <andrew@...n.ch>
> Cc: Gregory Clement <gregory.clement@...tlin.com>
> Cc: Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>
> Cc: Russell King <linux@...linux.org.uk>
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-kernel@...r.kernel.org

Applied on mvebu/arm

Thanks,

Gregory

> ---
>  arch/arm/mach-mvebu/pm-board.c | 11 ++++++++---
>  1 file changed, 8 insertions(+), 3 deletions(-)
>
> diff --git a/arch/arm/mach-mvebu/pm-board.c b/arch/arm/mach-mvebu/pm-board.c
> index db17121..1e2c17c 100644
> --- a/arch/arm/mach-mvebu/pm-board.c
> +++ b/arch/arm/mach-mvebu/pm-board.c
> @@ -79,7 +79,7 @@ static void mvebu_armada_pm_enter(void __iomem *sdram_reg, u32 srcmd)
>  static int __init mvebu_armada_pm_init(void)
>  {
>  	struct device_node *np;
> -	struct device_node *gpio_ctrl_np;
> +	struct device_node *gpio_ctrl_np = NULL;
>  	int ret = 0, i;
>  
>  	if (!of_machine_is_compatible("marvell,axp-gp"))
> @@ -126,18 +126,23 @@ static int __init mvebu_armada_pm_init(void)
>  			goto out;
>  		}
>  
> +		if(gpio_ctrl_np)
> +			of_node_put(gpio_ctrl_np);
>  		gpio_ctrl_np = args.np;
>  		pic_raw_gpios[i] = args.args[0];
>  	}
>  
>  	gpio_ctrl = of_iomap(gpio_ctrl_np, 0);
> -	if (!gpio_ctrl)
> -		return -ENOMEM;
> +	if (!gpio_ctrl) {
> +		ret = -ENOMEM;
> +		goto out;
> +	}
>  
>  	mvebu_pm_suspend_init(mvebu_armada_pm_enter);
>  
>  out:
>  	of_node_put(np);
> +	of_node_put(gpio_ctrl_np);
>  	return ret;
>  }
>  
> -- 
> 2.9.5
>

-- 
Gregory Clement, Bootlin
Embedded Linux and Kernel engineering
http://bootlin.com