Re: [PATCH v4 1/4] mm/gup: fix wrongly calculated returned value in fault_in_safe_writeable()

[Andrew Morton]

On Thu, 10 Apr 2025 11:57:14 +0800 Baoquan He <bhe@xxxxxxxxxx> wrote:

> Not like fault_in_readable() or fault_in_writeable(), in
> fault_in_safe_writeable() local variable 'start' is increased page
> by page to loop till the whole address range is handled. However,
> it mistakenly calcalates the size of handled range with 'uaddr - start'.

What are the userspace-visible runtime effects of this change?