diff options
| author | Jann Horn <jannh@google.com> | 2022-12-06 18:16:04 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-12-14 11:31:55 +0100 |
| commit | 4a1cdb49d0f2e865573d822ada4843f40f00bc8e (patch) | |
| tree | 0bbc94886f430bc5a958399dd030aeac069b3eb2 /mm | |
| parent | cdfd3739b2129f1bff2da552877e4a4b28c6e17c (diff) | |
mm/khugepaged: fix GUP-fast interaction by sending IPI
commit 2ba99c5e08812494bc57f319fb562f527d9bacd8 upstream.
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>
[manual backport: two of the three places in khugepaged that can free
ptes were refactored into a common helper between 5.15 and 6.0]
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/khugepaged.c | 3 | ||||
| -rw-r--r-- | mm/mmu_gather.c | 4 |
2 files changed, 4 insertions, 3 deletions
diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 014e8b259313..0268b549bd60 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1154,6 +1154,7 @@ static void collapse_huge_page(struct mm_struct *mm, _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); isolated = __collapse_huge_page_isolate(vma, address, pte, @@ -1538,6 +1539,7 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) /* step 4: collapse pmd */ _pmd = pmdp_collapse_flush(vma, haddr, pmd); mm_dec_nr_ptes(mm); + tlb_remove_table_sync_one(); pte_free(mm, pmd_pgtable(_pmd)); i_mmap_unlock_write(vma->vm_file->f_mapping); @@ -1625,6 +1627,7 @@ static void retract_page_tables(struct address_space *mapping, pgoff_t pgoff) /* assume page table is clear */ _pmd = pmdp_collapse_flush(vma, addr, pmd); mm_dec_nr_ptes(mm); + tlb_remove_table_sync_one(); pte_free(mm, pmd_pgtable(_pmd)); } mmap_write_unlock(mm); diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c index 03c33c93a582..205fdbb5792a 100644 --- a/mm/mmu_gather.c +++ b/mm/mmu_gather.c @@ -139,7 +139,7 @@ static void tlb_remove_table_smp_sync(void *arg) /* Simply deliver the interrupt */ } -static void tlb_remove_table_sync_one(void) +void tlb_remove_table_sync_one(void) { /* * This isn't an RCU grace period and hence the page-tables cannot be @@ -163,8 +163,6 @@ static void tlb_remove_table_free(struct mmu_table_batch *batch) #else /* !CONFIG_MMU_GATHER_RCU_TABLE_FREE */ -static void tlb_remove_table_sync_one(void) { } - static void tlb_remove_table_free(struct mmu_table_batch *batch) { __tlb_remove_table_free(batch); |