linux-kernel - Re: [PATCH] mfd: syscon: Don't free allocated name for regmap

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Date:   Tue, 8 Sep 2020 09:22:34 +0100
From:   Lee Jones <lee.jones@...aro.org>
To:     Marc Zyngier <maz@...nel.org>
Cc:     linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        Arnd Bergmann <arnd@...db.de>, Suman Anna <s-anna@...com>,
        kernel-team@...roid.com
Subject: Re: [PATCH] mfd: syscon: Don't free allocated name for regmap_config

On Thu, 03 Sep 2020, Marc Zyngier wrote:

> The name allocated for the regmap_config structure is freed
> pretty early, right after the registration of the MMIO region.
> 
> Unfortunately, that doesn't follow the life cycle that debugfs
> expects, as it can access the name field long after the free
> has occured.
> 
> Move the free on the error path, and keep it forever otherwise.
> 
> Fixes: e15d7f2b81d2 ("mfd: syscon: Use a unique name with regmap_config")
> Signed-off-by: Marc Zyngier <maz@...nel.org>
> ---
>  drivers/mfd/syscon.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)

Does this work for you Suman, Arnd?

> diff --git a/drivers/mfd/syscon.c b/drivers/mfd/syscon.c
> index 75859e492984..7a660411c562 100644
> --- a/drivers/mfd/syscon.c
> +++ b/drivers/mfd/syscon.c
> @@ -108,7 +108,6 @@ 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);
> @@ -145,6 +144,7 @@ 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);

-- 
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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