On Mon, Mar 13, 2017 at 08:22:13AM +0300, Kirill A. Shutemov wrote: > gup_p4d_range() should call gup_pud_range(), not itself. > > Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> > Reported-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx> > Fixes: c2febafc6773 ("mm: convert generic code to 5-level paging") > --- > mm/gup.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/gup.c b/mm/gup.c > index c74bad1bf6e8..04aa405350dc 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -1455,7 +1455,7 @@ static int gup_p4d_range(pgd_t pgd, unsigned long addr, unsigned long end, > if (!gup_huge_pd(__hugepd(p4d_val(p4d)), addr, > P4D_SHIFT, next, write, pages, nr)) > return 0; > - } else if (!gup_p4d_range(p4d, addr, next, write, pages, nr)) > + } else if (!gup_pud_range(p4d, addr, next, write, pages, nr)) > return 0; > } while (p4dp++, addr = next, addr != end); I just hit this on arm64, where the compiler was nice enough to warn me that something was amiss: mm/gup.c:1412:12: warning: 'gup_pud_range' defined but not used [-Wunused-function] static int gup_pud_range(p4d_t p4d, unsigned long addr, unsigned long end, ^ FWIW: Acked-by: Mark Rutland <mark.rutland@xxxxxxx> Mark.