diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 5515870b5b15..e9f4cbf50a2b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -5876,6 +5876,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, bool adjust_reservation; unsigned long last_addr_mask; + i_mmap_assert_write_locked(vma->vm_file->f_mapping); WARN_ON(!is_vm_hugetlb_page(vma)); BUG_ON(start & ~huge_page_mask(h)); BUG_ON(end & ~huge_page_mask(h)); @@ -5967,7 +5968,10 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, /* * Restore the reservation for anonymous page, otherwise the - * backing page could be stolen by someone. + * backing page could be stolen by someone. Restore only on the + * last unmap, otherwise the owner could empty its resv map + * while the folio is still mapped by a child. Note that holding + * i_mmap_lock_write is needed to check the number of mappings. * If there we are freeing a surplus, do not set the restore * reservation bit. */ @@ -5975,7 +5979,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, spin_lock_irq(&hugetlb_lock); if (!h->surplus_huge_pages && __vma_private_lock(vma) && - folio_test_anon(folio)) { + !folio_mapped(folio) && folio_test_anon(folio)) { folio_set_hugetlb_restore_reserve(folio); /* Reservation to be adjusted after the spin lock */ adjust_reservation = true; |