Re: [Minios-devel] [PATCH] lib/ukallocbbuddy: fix addmem call with negative len

[Simon Kuenzer <simon.kuenzer@xxxxxxxxx>]

Thanks a lot for this fix!

Reviewed-by: Simon Kuenzer <simon.kuenzer@xxxxxxxxx>

On 05.02.20 14:12, Hugo Lefeuvre wrote:
> Whenever len == metalen, the init region has exactly the size of the
> allocator metadata. In this case there is no space left for anything else
> and max - min - metalen is negative: calling bbuddy_addmem doesn't make
> sense.
>
> Only call bbuddy_addmem if there's memory left in the region.
> ---
>   lib/ukallocbbuddy/bbuddy.c | 9 ++++++---
>   1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/lib/ukallocbbuddy/bbuddy.c b/lib/ukallocbbuddy/bbuddy.c
> index 2a35de0..85f3e8d 100644
> --- a/lib/ukallocbbuddy/bbuddy.c
> +++ b/lib/ukallocbbuddy/bbuddy.c
> @@ -508,8 +508,11 @@ struct uk_alloc *uk_allocbbuddy_init(void *base, size_t 
> len)
>         a->availmem = bbuddy_availmem;
>   #endif
>   
> -	/* add left memory - ignore return value */
> -       bbuddy_addmem(a, (void *)(min + metalen),
> -                     (size_t)(max - min - metalen));
> +       if (max > min + metalen) {
> +               /* add left memory - ignore return value */
> +               bbuddy_addmem(a, (void *)(min + metalen),
> +                                (size_t)(max - min - metalen));
> +       }
> +
>         return a;
>   }
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