linux-kernel - Re: [PATCH] [soc/renesas] renesas-soc: Add error handling in renesas_soc

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Message-ID: <CAMuHMdUrd+LT3FnR255OWKQP-U2EXSpZ=7Q4k+pUZdy4es_vRQ@mail.gmail.com>
Date:   Thu, 30 Nov 2023 11:59:04 +0100
From:   Geert Uytterhoeven <geert@...ux-m68k.org>
To:     Haoran Liu <liuhaoran14@....com>
Cc:     magnus.damm@...il.com, linux-renesas-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] [soc/renesas] renesas-soc: Add error handling in renesas_soc_init

Hi Haoran,

Thanks for your patch!

On Wed, Nov 29, 2023 at 3:34 PM Haoran Liu <liuhaoran14@....com> wrote:
> This patch enhances the renesas_soc_init function in
> drivers/soc/renesas/renesas-soc.c by adding error handling for the
> of_property_read_string call. Previously, the function did not check
> for failure cases of of_property_read_string, which could lead to
> improper behavior if the required device tree properties were missing

Which improper behavior did you encounter? All of the
soc_device_attribute fields are optional, and drivers/base/soc.c
considers that when handling the machine field (sysfs_emit() handles
NULL pointer strings fine).

> or incorrect.

FTR, "model" is a required property of the root node.

> Although the error addressed by this patch may not occur in the current
> environment, I still suggest implementing these error handling routines
> if the function is not highly time-sensitive. As the environment evolves
> or the code gets reused in different contexts, there's a possibility that
> these errors might occur. Addressing them now can prevent potential
> debugging efforts in the future, which could be quite resource-intensive.
>
> Signed-off-by: Haoran Liu <liuhaoran14@....com>

> --- a/drivers/soc/renesas/renesas-soc.c
> +++ b/drivers/soc/renesas/renesas-soc.c
> @@ -487,7 +487,13 @@ static int __init renesas_soc_init(void)
>         }
>
>         np = of_find_node_by_path("/");
> -       of_property_read_string(np, "model", &soc_dev_attr->machine);
> +       ret = of_property_read_string(np, "model", &soc_dev_attr->machine);
> +       if (ret) {
> +               dev_err(dev, "Failed to read model property: %d\n", ret);

As reported by the kernel test robot:

    error: use of undeclared identifier 'dev'

Please do not submit completely untested patches.

> +               kfree(soc_dev_attr);
> +               return ret;

As the machine field is optional, there is no need for this check,
let alone to make this a fatal error condition.

> +       }
> +
>         of_node_put(np);
>
>         soc_dev_attr->family = kstrdup_const(family->name, GFP_KERNEL);

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds