Re: [PATCH] mm/mprotect: Fix do_mprotect_pkey() return on error

[Andrew Morton]

On Thu,  6 Apr 2023 15:30:50 -0400 "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> wrote:

> When the loop over the VMA is terminated early due to an error, the
> return code could be overwritten with ENOMEM.  Fix the return code by
> only setting the error on early loop termination when the error is not
> set.
> 
> Fixes: 2286a6914c77 ("mm: change mprotect_fixup to vma iterator")
> Cc: <stable@xxxxxxxxxxxxxxx>

I do think we should always describe the user-visible effects when
proposing a backport.

a) so the -stable maintainers understand why we're recommending the
   backport and

b) to help some poor soul who is looking at the patch wondering if
   it will fix his customer's bug report.

How's this?

: User-visible effects include: attempts to run mprotect() against a special
: mapping or with a poorly-aligned hugetlb address should return -EINVAL,
: but they presently return -ENOMEM.