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From:   Heiko Stuebner <heiko@sntech.de>
To:     Wen Yang <wen.yang99@zte.com.cn>
Cc:     linux-kernel@vger.kernel.org, wang.yi59@zte.com.cn,
        Russell King <linux@armlinux.org.uk>,
        linux-arm-kernel@lists.infradead.org,
        linux-rockchip@lists.infradead.org
Subject: Re: [PATCH v2 07/15] ARM: rockchip: fix a leaked reference by adding missing of_node_put
Date:   Tue, 23 Apr 2019 19:48:53 +0200
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References: <1551785646-46173-1-git-send-email-wen.yang99@zte.com.cn> <1551785646-46173-7-git-send-email-wen.yang99@zte.com.cn>
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Hi,

sorry that this took so long to look at, but I think it needs a bit of
rework, see below:

Am Dienstag, 5. M?rz 2019, 12:33:58 CEST schrieb 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-rockchip/pm.c:269:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 259, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/pm.c:275:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 259, but without a corresponding object release within this function
> ./arch/arm/mach-rockchip/platsmp.c:280:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 271, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:284:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 271, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:288:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 271, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:302:3-9: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 293, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:250:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 241, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:260:2-8: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 241, but without a corresponding object release within this function.
> ./arch/arm/mach-rockchip/platsmp.c:263:1-7: ERROR: missing of_node_put; acquired a node pointer with refcount incremented on line 241, but without a corresponding object release within this function.
> 
> Signed-off-by: Wen Yang <wen.yang99@zte.com.cn>
> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: Heiko Stuebner <heiko@sntech.de>
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-rockchip@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
> v2->v1: add a missing space between "adding" and "missing"
> 
>  arch/arm/mach-rockchip/platsmp.c | 12 ++++++++----
>  arch/arm/mach-rockchip/pm.c      | 11 ++++++-----
>  2 files changed, 14 insertions(+), 9 deletions(-)
> 
> diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
> index 51984a4..f93d64e 100644
> --- a/arch/arm/mach-rockchip/platsmp.c
> +++ b/arch/arm/mach-rockchip/platsmp.c
> @@ -277,19 +277,20 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
>  	sram_base_addr = of_iomap(node, 0);

just do the of_node_put here and drop the whole error gotos?
Because node in this case only holds the possible pointer to 

>  	if (!sram_base_addr) {
>  		pr_err("%s: could not map sram registers\n", __func__);
> -		return;
> +		goto out_put_node;
>  	}
>  
>  	if (has_pmu && rockchip_smp_prepare_pmu())
> -		return;
> +		goto out_put_node;
>  
>  	if (read_cpuid_part() == ARM_CPU_PART_CORTEX_A9) {
>  		if (rockchip_smp_prepare_sram(node))
> -			return;
> +			goto out_put_node;
>  
>  		/* enable the SCU power domain */
>  		pmu_set_power_domain(PMU_PWRDN_SCU, true);
>  
> +		of_node_put(node);
>  		node = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu");
>  		if (!node) {
>  			pr_err("%s: missing scu\n", __func__);
> @@ -299,7 +300,7 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
>  		scu_base_addr = of_iomap(node, 0);

similarly just put the scu node here?

>  		if (!scu_base_addr) {
>  			pr_err("%s: could not map scu registers\n", __func__);
> -			return;
> +			goto out_put_node;
>  		}
>  
>  		/*
> @@ -321,6 +322,9 @@ static void __init rockchip_smp_prepare_cpus(unsigned int max_cpus)
>  	/* Make sure that all cores except the first are really off */
>  	for (i = 1; i < ncores; i++)
>  		pmu_set_power_domain(0 + i, false);
> +
> +out_put_node:
> +	of_node_put(node);
>  }
>  
>  static void __init rk3036_smp_prepare_cpus(unsigned int max_cpus)
> diff --git a/arch/arm/mach-rockchip/pm.c b/arch/arm/mach-rockchip/pm.c
> index 0592534..43a16c9 100644
> --- a/arch/arm/mach-rockchip/pm.c
> +++ b/arch/arm/mach-rockchip/pm.c
> @@ -266,25 +266,26 @@ static int rk3288_suspend_init(struct device_node *np)
>  	rk3288_bootram_base = of_iomap(sram_np, 0);
>  	if (!rk3288_bootram_base) {
>  		pr_err("%s: could not map bootram base\n", __func__);

just add a regular of_node_put here?

> -		return -ENOMEM;
> +		ret = -ENOMEM;
> +		goto out_put_node;
>  	}
>  
>  	ret = of_address_to_resource(sram_np, 0, &res);
>  	if (ret) {
>  		pr_err("%s: could not get bootram phy addr\n", __func__);

and here as well? Not having to follow gotos might improve readability
especially as after here the node isn't used anymore as indicated by the
already existing of_node_put below which should be kept.


Heiko

> -		return ret;
> +		goto out_put_node;
>  	}
>  	rk3288_bootram_phy = res.start;
>  
> -	of_node_put(sram_np);
> -
>  	rk3288_config_bootdata();
>  
>  	/* copy resume code and data to bootsram */
>  	memcpy(rk3288_bootram_base, rockchip_slp_cpu_resume,
>  	       rk3288_bootram_sz);
>  
> -	return 0;
> +out_put_node:
> +	of_node_put(sram_np);
> +	return ret;
>  }
>  
>  static const struct platform_suspend_ops rk3288_suspend_ops = {
>