diff options
| author | Peter Xu <peterx@redhat.com> | 2022-12-16 16:52:19 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-01-19 02:12:39 +0100 |
| commit | 7d049f3a03ea705522210d70b9d3e223ef86d663 (patch) | |
| tree | e971ecc997880825dc2e2d2c53f66cbb53eb14ca /mm/hugetlb.c | |
| parent | mm/hugetlb: make userfaultfd_huge_must_wait() safe to pmd unshare (diff) | |
| download | linux-7d049f3a03ea705522210d70b9d3e223ef86d663.tar.xz linux-7d049f3a03ea705522210d70b9d3e223ef86d663.zip | |
mm/hugetlb: make hugetlb_follow_page_mask() safe to pmd unshare
Since hugetlb_follow_page_mask() walks the pgtable, it needs the vma lock
to make sure the pgtable page will not be freed concurrently.
Link: https://lkml.kernel.org/r/20221216155219.2043714-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 7f9db1d9f6a5..807edc1410e5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6396,9 +6396,10 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, if (WARN_ON_ONCE(flags & FOLL_PIN)) return NULL; + hugetlb_vma_lock_read(vma); pte = huge_pte_offset(mm, haddr, huge_page_size(h)); if (!pte) - return NULL; + goto out_unlock; ptl = huge_pte_lock(h, mm, pte); entry = huge_ptep_get(pte); @@ -6421,6 +6422,8 @@ struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, } out: spin_unlock(ptl); +out_unlock: + hugetlb_vma_unlock_read(vma); return page; } |