Re: [PATCH] nds32: fix up stack guard gap

From: Qiang Liu <cyruscyliu@gmail.com>
To: Hugh Dickins <hughd@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Nick Hu <nickhu@andestech.com>, Greentime Hu <green.hu@gmail.com>,
	Vincent Chen <deanbo422@gmail.com>,
	iLifetruth <yixiaonn@gmail.com>, Michal Hocko <mhocko@suse.com>,
	stable <stable@vger.kernel.org>
Subject: Re: [PATCH] nds32: fix up stack guard gap
Date: Wed, 30 Jun 2021 10:33:29 +0800	[thread overview]
Message-ID: <CAAKa2jn6LB14BYXJWoVoqgcqrjTYwJgLdDCa8mir=jOw6x5ZDA@mail.gmail.com> (raw)
In-Reply-To: <382e353f-7489-d8c8-5711-a2d99b0b7f0@google.com>

Hi,

On Wed, Jun 30, 2021 at 4:33 AM Hugh Dickins <hughd@google.com> wrote:
>
> On Tue, 29 Jun 2021, Greg Kroah-Hartman wrote:
>
> > Commit 1be7107fbe18 ("mm: larger stack guard gap, between vmas") fixed
> > up almost all architectures to deal with the stack guard gap, but forgit
> > nds32.
> >
> > Resolve this by properly fixing up the nsd32's version of
> > arch_get_unmapped_area()
> >
> > Reported-by: iLifetruth <yixiaonn@gmail.com>
> > Cc: Nick Hu <nickhu@andestech.com>
> > Cc: Greentime Hu <green.hu@gmail.com>
> > Cc: Vincent Chen <deanbo422@gmail.com>
> > Cc: Michal Hocko <mhocko@suse.com>
> > Cc: Hugh Dickins <hughd@google.com>
> > Cc: Qiang Liu <cyruscyliu@gmail.com>
> > Cc: stable <stable@vger.kernel.org>
> > Fixes: 1be7107fbe18 ("mm: larger stack guard gap, between vmas")
> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>
> Acked-by: Hugh Dickins <hughd@google.com>
>
> but it's a bit unfair to say that commit forgot nds32:
> nds32 came into the tree nearly a year later.
Could we use "not forward ported to"?

>
> > ---
> >  arch/nds32/mm/mmap.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/arch/nds32/mm/mmap.c b/arch/nds32/mm/mmap.c
> > index c206b31ce07a..1bdf5e7d1b43 100644
> > --- a/arch/nds32/mm/mmap.c
> > +++ b/arch/nds32/mm/mmap.c
> > @@ -59,7 +59,7 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr,
> >
> >               vma = find_vma(mm, addr);
> >               if (TASK_SIZE - len >= addr &&
> > -                 (!vma || addr + len <= vma->vm_start))
> > +                 (!vma || addr + len <= vm_start_gap(vma)))
> >                       return addr;
> >       }
> >
> > --
> > 2.32.0
> >
> >