Re: [PATCH v2] maple_tree: Use correct variable type in sizeof

[Andrew Morton]

On Tue, 11 Apr 2023 10:35:13 +0800 Peng Zhang <zhangpeng.00@xxxxxxxxxxxxx> wrote:

> The type of variable pointed to by pivs is unsigned long, but the type
> used in sizeof is a pointer type. Change it to unsigned long.

Thanks, but there's nothing in this changelog which explains why a
-stable backport is being proposed.  When fixing a bug, please always
describe the user-visible effects of that bug.

> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -3255,7 +3255,7 @@ static inline void mas_destroy_rebalance(struct ma_state *mas, unsigned char end
>  
>  		if (tmp < max_p)
>  			memset(pivs + tmp, 0,
> -			       sizeof(unsigned long *) * (max_p - tmp));
> +			       sizeof(unsigned long) * (max_p - tmp));
>  
>  		if (tmp < mt_slots[mt])
>  			memset(slots + tmp, 0, sizeof(void *) * (max_s - tmp));

Is there any situation in which
sizeof(unsigned long *) != sizeof(unsigned long)?