Re: [PATCH v3 1/5] kho: reject zero bootmem scale

["Pasha Tatashin" <pasha.tatashin@soleen.com>]

On Thu Nov 12, 2026 at 5:38 AM EST, Mike Rapoport (Microsoft) wrote:
> kho_bootmem=0% sets bootmem_scale to 0, and then the bootmem areas are
> sized using the explicit sizes that default to 0. KHO remains enabled,
> but there is no usable bootmem to load the next kernel.
>
> Reject zero scale the same way zero explicit sizes are rejected.
>
> Fixes: 3dc92c311498 ("kexec: add Kexec HandOver (KHO) generation helpers")
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
> ---
>  kernel/liveupdate/kexec_handover.c | 14 ++++++++++----
>  1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/kernel/liveupdate/kexec_handover.c b/kernel/liveupdate/kexec_handover.c
> index 6f1f55fe31819..b30ba686cb301 100644
> --- a/kernel/liveupdate/kexec_handover.c
> +++ b/kernel/liveupdate/kexec_handover.c
> @@ -703,16 +703,22 @@ static int __init kho_parse_bootmem_size(char *p)
>  	if (p[len - 1] == '%') {
>  		/* unsigned int max is 4,294,967,295, 10 chars */
>  		char s_scale[11] = {};
> +		unsigned int scale;
>  		int ret = 0;
>  
>  		if (len > ARRAY_SIZE(s_scale))
>  			return -EINVAL;
>  
>  		memcpy(s_scale, p, len - 1);
> -		ret = kstrtouint(s_scale, 10, &bootmem_scale);
> -		if (!ret)
> -			pr_notice("bootmem scale is %d%%\n", bootmem_scale);
> -		return ret;
> +		ret = kstrtouint(s_scale, 10, &scale);
> +		if (ret)
> +			return ret;
> +		if (!scale)
> +			return -EINVAL;
> +
> +		bootmem_scale = scale;
> +		pr_notice("bootmem scale is %d%%\n", bootmem_scale);
> +		return 0;

Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com> 

>  	}
>  
>  	/* parse ll[KMG],mm[KMG],nn[KMG] */





-- 
Pasha