diff options
| author | Peter Xu <[email protected]> | 2022-12-16 10:52:23 -0500 |
|---|---|---|
| committer | Andrew Morton <[email protected]> | 2023-01-18 17:12:39 -0800 |
| commit | eefc7fa53608920203a1402ecf7255ecfa8bb030 (patch) | |
| tree | 36b0442895fa08651d505d449c7eb1a3c96bd426 | |
| parent | 7d049f3a03ea705522210d70b9d3e223ef86d663 (diff) | |
mm/hugetlb: make follow_hugetlb_page() safe to pmd unshare
Since follow_hugetlb_page() 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/[email protected]
Signed-off-by: Peter Xu <[email protected]>
Acked-by: David Hildenbrand <[email protected]>
Reviewed-by: Mike Kravetz <[email protected]>
Reviewed-by: John Hubbard <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: James Houghton <[email protected]>
Cc: Jann Horn <[email protected]>
Cc: Miaohe Lin <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Nadav Amit <[email protected]>
Cc: Rik van Riel <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
| -rw-r--r-- | mm/hugetlb.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 807edc1410e5..da4c37553c08 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -6454,6 +6454,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, break; } + hugetlb_vma_lock_read(vma); /* * Some archs (sparc64, sh*) have multiple pte_ts to * each hugepage. We have to make sure we get the @@ -6478,6 +6479,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, !hugetlbfs_pagecache_present(h, vma, vaddr)) { if (pte) spin_unlock(ptl); + hugetlb_vma_unlock_read(vma); remainder = 0; break; } @@ -6499,6 +6501,8 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, if (pte) spin_unlock(ptl); + hugetlb_vma_unlock_read(vma); + if (flags & FOLL_WRITE) fault_flags |= FAULT_FLAG_WRITE; else if (unshare) @@ -6561,6 +6565,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, remainder -= pages_per_huge_page(h); i += pages_per_huge_page(h); spin_unlock(ptl); + hugetlb_vma_unlock_read(vma); continue; } @@ -6590,6 +6595,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, if (WARN_ON_ONCE(!try_grab_folio(pages[i], refs, flags))) { spin_unlock(ptl); + hugetlb_vma_unlock_read(vma); remainder = 0; err = -ENOMEM; break; @@ -6601,6 +6607,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, i += refs; spin_unlock(ptl); + hugetlb_vma_unlock_read(vma); } *nr_pages = remainder; /* |