Re: [PATCH v2 1/2] watchdog: use kstrtouint to parse softlockup_panic=

[Guenter Roeck <linux@roeck-us.net>]

On Tue, Sep 22, 2026 at 01:50:40PM +0800, 林濬哲 wrote:
> 
> simple_strtoul() is deprecated. Replace it with kstrtouint(). A bad
> value now leaves the variable unchanged and produces a warning,
> instead of being silently clamped.
> 
> __setup() handlers return whether they handled the option; there is
> no way to propagate parse errors, so the handler simply returns 1.
> 
> v2: warn on a bad value and return 1 instead of returning the parse
>     error, which __setup() handlers cannot do (Guenter Roeck).
> 
> Signed-off-by: Lin Junzhe <m18667909625@163.com>
> Assisted-by: AI coding assistant (disclosed per kernel AI guidelines)
> ---
>  kernel/watchdog.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/kernel/watchdog.c b/kernel/watchdog.c
> index e5134ad7b663..7f8c904554a9 100644
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -17,6 +17,7 @@
>  #include <linux/irq.h>
>  #include <linux/irqdesc.h>
>  #include <linux/kernel_stat.h>
> +#include <linux/kstrtox.h>
>  #include <linux/kvm_para.h>
>  #include <linux/math64.h>
>  #include <linux/mm.h>
> @@ -422,7 +423,11 @@ static unsigned long soft_lockup_nmi_warn;
>  
>  static int __init softlockup_panic_setup(char *str)
>  {
> -	softlockup_panic = simple_strtoul(str, NULL, 0);
> +	int ret;
> +
> +	ret = kstrtouint(str, 0, &softlockup_panic);
> +	if (ret)
> +		pr_warn("softlockup_panic: bad option string '%s'\n", str);

Hardly any other __setup function warns here, and I do not see the point
adding it here.

Guenter

>  	return 1;
>  }
>  __setup("softlockup_panic=", softlockup_panic_setup);
> -- 
> 2.54.0.windows.1
> 
>