diff options
| author | Jann Horn <jannh@google.com> | 2022-11-25 22:37:13 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2022-11-30 23:49:42 +0100 |
| commit | 2ba99c5e08812494bc57f319fb562f527d9bacd8 (patch) | |
| tree | 2a2cdaaa8a0bd83cc2e1a1feb93c6772a681a3cd /mm/khugepaged.c | |
| parent | mm/khugepaged: take the right locks for page table retraction (diff) | |
| download | linux-2ba99c5e08812494bc57f319fb562f527d9bacd8.tar.xz linux-2ba99c5e08812494bc57f319fb562f527d9bacd8.zip | |
mm/khugepaged: fix GUP-fast interaction by sending IPI
Since commit 70cbc3cc78a99 ("mm: gup: fix the fast GUP race against THP
collapse"), the lockless_pages_from_mm() fastpath rechecks the pmd_t to
ensure that the page table was not removed by khugepaged in between.
However, lockless_pages_from_mm() still requires that the page table is
not concurrently freed. Fix it by sending IPIs (if the architecture uses
semi-RCU-style page table freeing) before freeing/reusing page tables.
Link: https://lkml.kernel.org/r/20221129154730.2274278-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221128180252.1684965-2-jannh@google.com
Link: https://lkml.kernel.org/r/20221125213714.4115729-2-jannh@google.com
Fixes: ba76149f47d8 ("thp: khugepaged")
Signed-off-by: Jann Horn <jannh@google.com>
Reviewed-by: Yang Shi <shy828301@gmail.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/khugepaged.c')
| -rw-r--r-- | mm/khugepaged.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 0a11e132ad6b..294cb75d9c22 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1051,6 +1051,7 @@ static int collapse_huge_page(struct mm_struct *mm, unsigned long address, _pmd = pmdp_collapse_flush(vma, address, pmd); spin_unlock(pmd_ptl); mmu_notifier_invalidate_range_end(&range); + tlb_remove_table_sync_one(); spin_lock(pte_ptl); result = __collapse_huge_page_isolate(vma, address, pte, cc, @@ -1410,6 +1411,7 @@ static void collapse_and_free_pmd(struct mm_struct *mm, struct vm_area_struct *v lockdep_assert_held_write(&vma->anon_vma->root->rwsem); pmd = pmdp_collapse_flush(vma, addr, pmdp); + tlb_remove_table_sync_one(); mm_dec_nr_ptes(mm); page_table_check_pte_clear_range(mm, addr, pmd); pte_free(mm, pmd_pgtable(pmd)); |