On 3/22/21 10:51 AM, Peter Xu wrote: > When uffd-minor enabled, we need to put the page cache before handling the > userfault in hugetlb_no_page(), otherwise the page refcount got leaked. > > This can be reproduced by running userfaultfd selftest with hugetlb_shared > mode, then cat /proc/meminfo. > > Cc: Axel Rasmussen <[email protected]> > Cc: Andrea Arcangeli <[email protected]> > Cc: Mike Kravetz <[email protected]> > Cc: Mike Rapoport <[email protected]> > Cc: Andrew Morton <[email protected]> > Fixes: f2bf15fb0969 ("userfaultfd: add minor fault registration mode") > Signed-off-by: Peter Xu <[email protected]> > --- > mm/hugetlb.c | 1 + > 1 file changed, 1 insertion(+)
Thanks for finding/fixing. Reviewed-by: Mike Kravetz <[email protected]> I think this is just in Andrew's tree. So it will need to be fixed there. -- Mike Kravetz > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index 408dbc08298a..56b78a206913 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -4449,6 +4449,7 @@ static vm_fault_t hugetlb_no_page(struct mm_struct *mm, > /* Check for page in userfault range. */ > if (userfaultfd_minor(vma)) { > unlock_page(page); > + put_page(page); > ret = hugetlb_handle_userfault(vma, mapping, idx, > flags, haddr, > VM_UFFD_MINOR); >
