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| author |   Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2016-07-26 15:25:12 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2016-07-26 16:19:19 -0700 |
| commit | 1f52e67e5e7f48424059f8168e3a65bddc80ad97 (patch) | |
| tree | 2719a0782dd6af0708d27564392a8beb9e4e3f8e /mm/huge_memory.c | |
| parent | mm, thp: fix locking inconsistency in collapse_huge_page (diff) | |
| download | linux-dev-1f52e67e5e7f48424059f8168e3a65bddc80ad97.tar.xz linux-dev-1f52e67e5e7f48424059f8168e3a65bddc80ad97.zip | |
khugepaged: recheck pmd after mmap_sem re-acquired
Vlastimil noted[1] that pmd can be no longer valid after we drop
mmap_sem. We need recheck it once mmap_sem taken again.
[1] http://lkml.kernel.org/r/12918dcd-a695-c6f4-e06f-69141c5f357f@suse.cz
Link: http://lkml.kernel.org/r/1466021202-61880-6-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/huge_memory.c')
| -rw-r--r-- | mm/huge_memory.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 1841e0ceac23..1a90f55d930f 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2433,6 +2433,9 @@ static bool __collapse_huge_page_swapin(struct mm_struct *mm, /* vma is no longer available, don't continue to swapin */ if (hugepage_vma_revalidate(mm, address)) return false; + /* check if the pmd is still valid */ + if (mm_find_pmd(mm, address) != pmd) + return false; } if (ret & VM_FAULT_ERROR) { trace_mm_collapse_huge_page_swapin(mm, swapped_in, 0); @@ -2518,6 +2521,9 @@ static void collapse_huge_page(struct mm_struct *mm, result = hugepage_vma_revalidate(mm, address); if (result) goto out; + /* check if the pmd is still valid */ + if (mm_find_pmd(mm, address) != pmd) + goto out; anon_vma_lock_write(vma->anon_vma); |