Re: [PATCH] crash_core: optimize crash_exclude_mem_range()

[Andrew Morton]

On Wed, 20 Dec 2023 00:34:18 +0800 Yuntao Wang <ytcoode@xxxxxxxxx> wrote:

> Because memory ranges in mem->ranges are stored in ascending order, when we
> detect `p_end < start`, we can break the for loop early, as the subsequent
> memory ranges must also be outside the range we are looking for.
> 
> Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx>
> ---
> Hi Andrew,
> 
> Patch "[PATCH 2/2] crash_core: fix out-of-bounds access check in
> crash_exclude_mem_range()" can be ignored, use this patch instead.
> 

Some reviewer input on this would be helpful please?

> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -575,9 +575,12 @@ int crash_exclude_mem_range(struct crash_mem *mem,
>  		p_start = mstart;
>  		p_end = mend;
>  
> -		if (p_start > end || p_end < start)
> +		if (p_start > end)
>  			continue;
>  
> +		if (p_end < start)
> +			break;
> +
>  		/* Truncate any area outside of range */
>  		if (p_start < start)
>  			p_start = start;
> -- 
> 2.43.0