On 9/19/18 7:03 PM, Yang Shi wrote: > When unmapping VM_HUGETLB mappings, vm flags need to be updated. Since > the vmas have been detached, so it sounds safe to update vm flags with > read mmap_sem. > > Cc: Michal Hocko <mhocko@xxxxxxxxxx> > Cc: Vlastimil Babka <vbabka@xxxxxxx> > Reviewed-by: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Signed-off-by: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> > --- > mm/mmap.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/mmap.c b/mm/mmap.c > index 982dd00..490340e 100644 > --- a/mm/mmap.c > +++ b/mm/mmap.c > @@ -2777,7 +2777,7 @@ static int __do_munmap(struct mm_struct *mm, unsigned long start, size_t len, > * update vm_flags. > */ > if (downgrade && > - (tmp->vm_flags & (VM_HUGETLB | VM_PFNMAP))) > + (tmp->vm_flags & VM_PFNMAP)) > downgrade = false; > > tmp = tmp->vm_next; >
