--- x/mm/hugetlb.c
+++ y/mm/hugetlb.c
@@ -4923,6 +4923,7 @@ int copy_hugetlb_page_range(struct mm_st
 					src_vma->vm_end);
 		mmu_notifier_invalidate_range_start(&range);
 		vma_assert_write_locked(src_vma);
+		hugetlb_vma_lock_write(src_vma);
 		raw_write_seqcount_begin(&src->write_protect_seq);
 	} else {
 		/*
@@ -5084,6 +5085,7 @@ again:
 
 	if (cow) {
 		raw_write_seqcount_end(&src->write_protect_seq);
+		hugetlb_vma_unlock_write(src_vma);
 		mmu_notifier_invalidate_range_end(&range);
 	} else {
 		hugetlb_vma_unlock_read(src_vma);