From 04dee9e85cf50a2f24738e456d66b88de109b806 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Thu, 8 Jun 2023 18:29:22 -0700 Subject: [PATCH] mm/various: give up if pte_offset_map[_lock]() fails MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Following the examples of nearby code, various functions can just give up if pte_offset_map() or pte_offset_map_lock() fails. And there's no need for a preliminary pmd_trans_unstable() or other such check, since such cases are now safely handled inside. Link: https://lkml.kernel.org/r/7b9bd85d-1652-cbf2-159d-f503b45e5b@google.com Signed-off-by: Hugh Dickins Cc: Alistair Popple Cc: Anshuman Khandual Cc: Axel Rasmussen Cc: Christophe Leroy Cc: Christoph Hellwig Cc: David Hildenbrand Cc: "Huang, Ying" Cc: Ira Weiny Cc: Jason Gunthorpe Cc: Kirill A. Shutemov Cc: Lorenzo Stoakes Cc: Matthew Wilcox Cc: Mel Gorman Cc: Miaohe Lin Cc: Mike Kravetz Cc: Mike Rapoport (IBM) Cc: Minchan Kim Cc: Naoya Horiguchi Cc: Pavel Tatashin Cc: Peter Xu Cc: Peter Zijlstra Cc: Qi Zheng Cc: Ralph Campbell Cc: Ryan Roberts Cc: SeongJae Park Cc: Song Liu Cc: Steven Price Cc: Suren Baghdasaryan Cc: Thomas Hellström Cc: Will Deacon Cc: Yang Shi Cc: Yu Zhao Cc: Zack Rusin Signed-off-by: Andrew Morton --- mm/gup.c | 9 ++++++--- mm/ksm.c | 7 ++++--- mm/memcontrol.c | 8 ++++---- mm/memory-failure.c | 8 +++++--- mm/migrate.c | 3 +++ 5 files changed, 22 insertions(+), 13 deletions(-) diff --git a/mm/gup.c b/mm/gup.c index d448fd2..598e8c9 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -545,10 +545,10 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, if (WARN_ON_ONCE((flags & (FOLL_PIN | FOLL_GET)) == (FOLL_PIN | FOLL_GET))) return ERR_PTR(-EINVAL); - if (unlikely(pmd_bad(*pmd))) - return no_page_table(vma, flags); ptep = pte_offset_map_lock(mm, pmd, address, &ptl); + if (!ptep) + return no_page_table(vma, flags); pte = *ptep; if (!pte_present(pte)) goto no_page; @@ -852,8 +852,9 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address, pmd = pmd_offset(pud, address); if (!pmd_present(*pmd)) return -EFAULT; - VM_BUG_ON(pmd_trans_huge(*pmd)); pte = pte_offset_map(pmd, address); + if (!pte) + return -EFAULT; if (pte_none(*pte)) goto unmap; *vma = get_gate_vma(mm); @@ -2468,6 +2469,8 @@ static int gup_pte_range(pmd_t pmd, pmd_t *pmdp, unsigned long addr, pte_t *ptep, *ptem; ptem = ptep = pte_offset_map(&pmd, addr); + if (!ptep) + return 0; do { pte_t pte = ptep_get_lockless(ptep); struct page *page; diff --git a/mm/ksm.c b/mm/ksm.c index df2aa28..3dc1545 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -431,10 +431,9 @@ static int break_ksm_pmd_entry(pmd_t *pmd, unsigned long addr, unsigned long nex pte_t *pte; int ret; - if (pmd_leaf(*pmd) || !pmd_present(*pmd)) - return 0; - pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl); + if (!pte) + return 0; if (pte_present(*pte)) { page = vm_normal_page(walk->vma, addr, *pte); } else if (!pte_none(*pte)) { @@ -1203,6 +1202,8 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, mmu_notifier_invalidate_range_start(&range); ptep = pte_offset_map_lock(mm, pmd, addr, &ptl); + if (!ptep) + goto out_mn; if (!pte_same(*ptep, orig_pte)) { pte_unmap_unlock(ptep, ptl); goto out_mn; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index caf6ab5..77d8d2d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6021,9 +6021,9 @@ static int mem_cgroup_count_precharge_pte_range(pmd_t *pmd, return 0; } - if (pmd_trans_unstable(pmd)) - return 0; pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!pte) + return 0; for (; addr != end; pte++, addr += PAGE_SIZE) if (get_mctgt_type(vma, addr, *pte, NULL)) mc.precharge++; /* increment precharge temporarily */ @@ -6241,10 +6241,10 @@ static int mem_cgroup_move_charge_pte_range(pmd_t *pmd, return 0; } - if (pmd_trans_unstable(pmd)) - return 0; retry: pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl); + if (!pte) + return 0; for (; addr != end; addr += PAGE_SIZE) { pte_t ptent = *(pte++); bool device = false; diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 004a02f..d5116f0 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -405,6 +405,8 @@ static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct *vma, if (pmd_devmap(*pmd)) return PMD_SHIFT; pte = pte_offset_map(pmd, address); + if (!pte) + return 0; if (pte_present(*pte) && pte_devmap(*pte)) ret = PAGE_SHIFT; pte_unmap(pte); @@ -791,11 +793,11 @@ static int hwpoison_pte_range(pmd_t *pmdp, unsigned long addr, goto out; } - if (pmd_trans_unstable(pmdp)) - goto out; - mapped_pte = ptep = pte_offset_map_lock(walk->vma->vm_mm, pmdp, addr, &ptl); + if (!ptep) + goto out; + for (; addr != end; ptep++, addr += PAGE_SIZE) { ret = check_hwpoisoned_entry(*ptep, addr, PAGE_SHIFT, hwp->pfn, &hwp->tk); diff --git a/mm/migrate.c b/mm/migrate.c index c1f2c40..3635629 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -305,6 +305,9 @@ void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd, swp_entry_t entry; ptep = pte_offset_map_lock(mm, pmd, address, &ptl); + if (!ptep) + return; + pte = *ptep; pte_unmap(ptep); -- 2.7.4