linux-kernel - RE: [v2][PATCH] Revert "mfd: syscon: Don't free allocated name for regmap

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Date:   Mon, 22 Feb 2021 03:45:12 +0000
From:   "Li, Meng" <Meng.Li@...driver.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "maz@...nel.org" <maz@...nel.org>,
        "lee.jones@...aro.org" <lee.jones@...aro.org>,
        "arnd@...db.de" <arnd@...db.de>,
        "Hao, Kexin" <Kexin.Hao@...driver.com>
Subject: RE: [v2][PATCH] Revert "mfd: syscon: Don't free allocated name for
 regmap_config"

Hi Marc&Lee,

Is there any comment on this patch?
Could you please help to review this patch so that I can improve it if it still has weakness?

Thanks,
Limeng

> -----Original Message-----
> From: Li, Meng <Meng.Li@...driver.com>
> Sent: Friday, January 15, 2021 9:51 AM
> To: linux-kernel@...r.kernel.org
> Cc: maz@...nel.org; lee.jones@...aro.org; arnd@...db.de; Hao, Kexin
> <Kexin.Hao@...driver.com>; Li, Meng <Meng.Li@...driver.com>
> Subject: [v2][PATCH] Revert "mfd: syscon: Don't free allocated name for
> regmap_config"
> 
> From: Limeng <Meng.Li@...driver.com>
> 
> This reverts commit 529a1101212a785c5df92c314b0e718287150c3b.
> 
> The reverted patch moves the memory free to error path, but introduce a
> memory leak. There is another commit 94cc89eb8fa5("regmap: debugfs:
> Fix handling of name string for debugfs init delays") fixing this debugfs init
> issue from root cause. With this fixing, the name field in struct
> regmap_debugfs_node is removed. When initialize debugfs for syscon driver,
> the name field of struct regmap_config is not used anymore. So, revert this
> patch directly to avoid memory leak.
> 
> v2:
> Notify the author of the reverted commit by adding Cc:
> 
> Fixes: 529a1101212a("mfd: syscon: Don't free allocated name for
> regmap_config")
> Cc: Marc Zyngier <maz@...nel.org>
> Cc: stable@...r.kernel.org
> Signed-off-by: Meng Li <Meng.Li@...driver.com>
> ---
>  drivers/mfd/syscon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c index
> ca465794ea9c..df5cebb372a5 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -108,6 +108,7 @@ static struct syscon *of_syscon_register(struct
> device_node *np, bool check_clk)
>  	syscon_config.max_register = resource_size(&res) - reg_io_width;
> 
>  	regmap = regmap_init_mmio(NULL, base, &syscon_config);
> +	kfree(syscon_config.name);
>  	if (IS_ERR(regmap)) {
>  		pr_err("regmap init failed\n");
>  		ret = PTR_ERR(regmap);
> @@ -144,7 +145,6 @@ static struct syscon *of_syscon_register(struct
> device_node *np, bool check_clk)
>  	regmap_exit(regmap);
>  err_regmap:
>  	iounmap(base);
> -	kfree(syscon_config.name);
>  err_map:
>  	kfree(syscon);
>  	return ERR_PTR(ret);
> --
> 2.17.1