From: Ryan Roberts <ryan.roberts@arm.com> mainline inclusion from mainline-v6.5-rc1 commit c11d34fa139e4b0fb4249a30f37b178353533fa1 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IBDTU7 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- It is racy to non-atomically read a pte, then clear the young bit, then write it back as this could discard dirty information. Further, it is bad practice to directly set a pte entry within a table. Instead clearing young must go through the arch-provided helper, ptep_test_and_clear_young() to ensure it is modified atomically and to give the arch code visibility and allow it to check (and potentially modify) the operation. Link: https://lkml.kernel.org/r/20230602092949.545577-3-ryan.roberts@arm.com Fixes: 3f49584b262c ("mm/damon: implement primitives for the virtual memory address spaces"). Signed-off-by: Ryan Roberts <ryan.roberts@arm.com> Reviewed-by: Zi Yan <ziy@nvidia.com> Reviewed-by: SeongJae Park <sj@kernel.org> Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org> Cc: Christoph Hellwig <hch@lst.de> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Lorenzo Stoakes <lstoakes@gmail.com> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Uladzislau Rezki (Sony) <urezki@gmail.com> Cc: Yu Zhao <yuzhao@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ze Zuo <zuoze1@huawei.com> --- mm/damon/ops-common.c | 16 ++++++---------- mm/damon/ops-common.h | 4 ++-- mm/damon/paddr.c | 4 ++-- mm/damon/vaddr.c | 4 ++-- 4 files changed, 12 insertions(+), 16 deletions(-) diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c index 75409601f934..13b99975cbc2 100644 --- a/mm/damon/ops-common.c +++ b/mm/damon/ops-common.c @@ -33,7 +33,7 @@ struct page *damon_get_page(unsigned long pfn) return page; } -void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr) +void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr) { bool referenced = false; struct page *page = damon_get_page(pte_pfn(*pte)); @@ -41,13 +41,11 @@ void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr) if (!page) return; - if (pte_young(*pte)) { + if (ptep_test_and_clear_young(vma, addr, pte)) referenced = true; - *pte = pte_mkold(*pte); - } #ifdef CONFIG_MMU_NOTIFIER - if (mmu_notifier_clear_young(mm, addr, addr + PAGE_SIZE)) + if (mmu_notifier_clear_young(vma->vm_mm, addr, addr + PAGE_SIZE)) referenced = true; #endif /* CONFIG_MMU_NOTIFIER */ @@ -58,7 +56,7 @@ void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr) put_page(page); } -void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr) +void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr) { #ifdef CONFIG_TRANSPARENT_HUGEPAGE bool referenced = false; @@ -67,13 +65,11 @@ void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr) if (!page) return; - if (pmd_young(*pmd)) { + if (pmdp_test_and_clear_young(vma, addr, pmd)) referenced = true; - *pmd = pmd_mkold(*pmd); - } #ifdef CONFIG_MMU_NOTIFIER - if (mmu_notifier_clear_young(mm, addr, addr + HPAGE_PMD_SIZE)) + if (mmu_notifier_clear_young(vma->vm_mm, addr, addr + HPAGE_PMD_SIZE)) referenced = true; #endif /* CONFIG_MMU_NOTIFIER */ diff --git a/mm/damon/ops-common.h b/mm/damon/ops-common.h index 8d82d3722204..e062a8874e41 100644 --- a/mm/damon/ops-common.h +++ b/mm/damon/ops-common.h @@ -9,8 +9,8 @@ struct page *damon_get_page(unsigned long pfn); -void damon_ptep_mkold(pte_t *pte, struct mm_struct *mm, unsigned long addr); -void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr); +void damon_ptep_mkold(pte_t *pte, struct vm_area_struct *vma, unsigned long addr); +void damon_pmdp_mkold(pmd_t *pmd, struct vm_area_struct *vma, unsigned long addr); int damon_cold_score(struct damon_ctx *c, struct damon_region *r, struct damos *s); diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index 5945e1e37938..0b3927d0b4a8 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -28,9 +28,9 @@ static bool __damon_pa_mkold(struct page *page, struct vm_area_struct *vma, while (page_vma_mapped_walk(&pvmw)) { addr = pvmw.address; if (pvmw.pte) - damon_ptep_mkold(pvmw.pte, vma->vm_mm, addr); + damon_ptep_mkold(pvmw.pte, vma, addr); else - damon_pmdp_mkold(pvmw.pmd, vma->vm_mm, addr); + damon_pmdp_mkold(pvmw.pmd, vma, addr); } return true; } diff --git a/mm/damon/vaddr.c b/mm/damon/vaddr.c index 4c953e4701f0..a21792f1348f 100644 --- a/mm/damon/vaddr.c +++ b/mm/damon/vaddr.c @@ -310,7 +310,7 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr, } if (pmd_trans_huge(*pmd)) { - damon_pmdp_mkold(pmd, walk->mm, addr); + damon_pmdp_mkold(pmd, walk->vma, addr); spin_unlock(ptl); return 0; } @@ -322,7 +322,7 @@ static int damon_mkold_pmd_entry(pmd_t *pmd, unsigned long addr, pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); if (!pte_present(*pte)) goto out; - damon_ptep_mkold(pte, walk->mm, addr); + damon_ptep_mkold(pte, walk->vma, addr); out: pte_unmap_unlock(pte, ptl); return 0; -- 2.25.1