linux-kernel - Re: [PATCH] clk: imx93: fix memory leak and missing unwind goto in imx93_clocks

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Message-ID: <ZGY4DQ7JKvC1fMyt@linaro.org>
Date:   Thu, 18 May 2023 17:37:01 +0300
From:   Abel Vesa <abel.vesa@...aro.org>
To:     Zhanhao Hu <zero12113@...t.edu.cn>
Cc:     Abel Vesa <abelvesa@...nel.org>, Peng Fan <peng.fan@....com>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Shawn Guo <shawnguo@...nel.org>,
        Sascha Hauer <s.hauer@...gutronix.de>,
        Pengutronix Kernel Team <kernel@...gutronix.de>,
        Fabio Estevam <festevam@...il.com>,
        NXP Linux Team <linux-imx@....com>,
        hust-os-kernel-patches@...glegroups.com,
        Dongliang Mu <dzm91@...t.edu.cn>, linux-clk@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] clk: imx93: fix memory leak and missing unwind goto in
 imx93_clocks_probe

On 23-04-26 14:25:52, Zhanhao Hu wrote:
> In function probe(), it returns directly without unregistered hws
> when error occurs.
> 
> I fix this by adding 'goto unregister_hws;' on line 295 and
> line 310.

Hi Zhanhao,

I like your patch, but there are some things to improve in the commit
message.

Have a read here before rephrasing it:
https://docs.kernel.org/process/submitting-patches.html

Quoting the above doc:
"Describe your changes in imperative mood, e.g. "make xyzzy do frotz"
instead of "[This patch] makes xyzzy do frotz" or "[I] changed xyzzy to
do frotz", as if you are giving orders to the codebase to change its
behaviour."

> 
> Besides, I use devm_kzalloc() instead of kzalloc() to automatically
> free the memory using devm_kfree() when error occurs.

So this should be rephrased like:

Use devm_kzalloc instead of kzalloc, to automatically free the memory...

> 
> Similarly, I replace of_iomap() with devm_of_iomap() to automatically
> handle the unused ioremap region. So I delete 'iounmap(anatop_base);'
> in unregister_hws.

Same here. Make it imperative rather than mentioning what you're doing
in this patch.

With the commit rephrased in a new version, I'll be more than happy to
apply it.

> 
> Fixes: 24defbe194b6 ("clk: imx: add i.MX93 clk")
> Signed-off-by: Zhanhao Hu <zero12113@...t.edu.cn>
> Reviewed-by: Dongliang Mu <dzm91@...t.edu.cn>
> ---
> This issue is found by static analysis and remains untested.
> ---
>  drivers/clk/imx/clk-imx93.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/clk/imx/clk-imx93.c b/drivers/clk/imx/clk-imx93.c
> index 07b4a043e449..b6c7c2725906 100644
> --- a/drivers/clk/imx/clk-imx93.c
> +++ b/drivers/clk/imx/clk-imx93.c
> @@ -264,7 +264,7 @@ static int imx93_clocks_probe(struct platform_device *pdev)
>  	void __iomem *base, *anatop_base;
>  	int i, ret;
>  
> -	clk_hw_data = kzalloc(struct_size(clk_hw_data, hws,
> +	clk_hw_data = devm_kzalloc(dev, struct_size(clk_hw_data, hws,
>  					  IMX93_CLK_END), GFP_KERNEL);
>  	if (!clk_hw_data)
>  		return -ENOMEM;
> @@ -288,10 +288,12 @@ static int imx93_clocks_probe(struct platform_device *pdev)
>  								    "sys_pll_pfd2", 1, 2);
>  
>  	np = of_find_compatible_node(NULL, NULL, "fsl,imx93-anatop");
> -	anatop_base = of_iomap(np, 0);
> +	anatop_base = devm_of_iomap(dev, np, 0, NULL);
>  	of_node_put(np);
> -	if (WARN_ON(!anatop_base))
> -		return -ENOMEM;
> +	if (WARN_ON(IS_ERR(anatop_base))) {
> +		ret = PTR_ERR(base);
> +		goto unregister_hws;
> +	}
>  
>  	clks[IMX93_CLK_ARM_PLL] = imx_clk_fracn_gppll_integer("arm_pll", "osc_24m",
>  							      anatop_base + 0x1000,
> @@ -304,8 +306,8 @@ static int imx93_clocks_probe(struct platform_device *pdev)
>  	np = dev->of_node;
>  	base = devm_platform_ioremap_resource(pdev, 0);
>  	if (WARN_ON(IS_ERR(base))) {
> -		iounmap(anatop_base);
> -		return PTR_ERR(base);
> +		ret = PTR_ERR(base);
> +		goto unregister_hws;
>  	}
>  
>  	for (i = 0; i < ARRAY_SIZE(root_array); i++) {
> @@ -345,7 +347,6 @@ static int imx93_clocks_probe(struct platform_device *pdev)
>  
>  unregister_hws:
>  	imx_unregister_hw_clocks(clks, IMX93_CLK_END);
> -	iounmap(anatop_base);
>  
>  	return ret;
>  }
> -- 
> 2.34.1
>