Re: [PATCH] drivers/virt/fsl_hypervisor: Correcting error handling path

[Souptick Joarder]

On Fri, May 22, 2020 at 6:24 PM Dan Carpenter <dan.carpenter@xxxxxxxxxx> wrote:
>
> On Thu, May 14, 2020 at 01:53:16AM +0530, Souptick Joarder wrote:
> > First, when memory allocation for sg_list_unaligned failed, there
> > is no point of calling put_pages() as we haven't pinned any pages.
> >
> > Second, if get_user_pages_fast() failed we should unpinned num_pinned
> > pages, no point of checking till num_pages.
> >
> > This will address both.
> >
> > Signed-off-by: Souptick Joarder <jrdr.linux@xxxxxxxxx>
>
> If gup_flags were | FOLL_LONGTERM then this patch would fix a double
> free because of the put_page() in __gup_longterm_locked().
>
> mm/gup.c
>   1786                  if (check_dax_vmas(vmas_tmp, rc)) {
>   1787                          for (i = 0; i < rc; i++)
>   1788                                  put_page(pages[i]);
>                                         ^^^^^^^^^^^^^^^^^^^
> put_page() here and also in the caller.
>
>   1789                          rc = -EOPNOTSUPP;
>   1790                          goto out;
>   1791                  }
>
> But since this isn't FOLL_LONGTERM the patch is a nice cleanup which
> doesn't affect run time.
>
> Reviewed-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

Hi Andrew,
Is it fine to take it through mm tree ?