The patch titled
Subject: mm/various: give up if pte_offset_map[_lock]() fails
has been added to the -mm mm-unstable branch. Its filename is
mm-various-give-up-if-pte_offset_map-fails.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-various-give-up-if-pte_offset_map-fails.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: mm/various: give up if pte_offset_map[_lock]() fails
Date: Thu, 8 Jun 2023 18:29:22 -0700 (PDT)
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@xxxxxxxxxx
Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Alistair Popple <apopple@xxxxxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: "Huang, Ying" <ying.huang@xxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport (IBM) <rppt@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Pavel Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Peter Xu <peterx@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Cc: Ralph Campbell <rcampbell@xxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: SeongJae Park <sj@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Cc: Steven Price <steven.price@xxxxxxx>
Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx>
Cc: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zack Rusin <zackr@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
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(-)
--- a/mm/gup.c~mm-various-give-up-if-pte_offset_map-fails
+++ a/mm/gup.c
@@ -545,10 +545,10 @@ static struct page *follow_page_pte(stru
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_struc
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_
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;
--- a/mm/ksm.c~mm-various-give-up-if-pte_offset_map-fails
+++ a/mm/ksm.c
@@ -431,10 +431,9 @@ static int break_ksm_pmd_entry(pmd_t *pm
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_s
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;
--- a/mm/memcontrol.c~mm-various-give-up-if-pte_offset_map-fails
+++ a/mm/memcontrol.c
@@ -6021,9 +6021,9 @@ static int mem_cgroup_count_precharge_pt
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_ra
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;
--- a/mm/memory-failure.c~mm-various-give-up-if-pte_offset_map-fails
+++ a/mm/memory-failure.c
@@ -405,6 +405,8 @@ static unsigned long dev_pagemap_mapping
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 *pmd
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);
--- a/mm/migrate.c~mm-various-give-up-if-pte_offset_map-fails
+++ a/mm/migrate.c
@@ -305,6 +305,9 @@ void migration_entry_wait(struct mm_stru
swp_entry_t entry;
ptep = pte_offset_map_lock(mm, pmd, address, &ptl);
+ if (!ptep)
+ return;
+
pte = *ptep;
pte_unmap(ptep);
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
arm-allow-pte_offset_map-to-fail.patch
arm64-allow-pte_offset_map-to-fail.patch
arm64-hugetlb-pte_alloc_huge-pte_offset_huge.patch
ia64-hugetlb-pte_alloc_huge-pte_offset_huge.patch
m68k-allow-pte_offset_map-to-fail.patch
microblaze-allow-pte_offset_map-to-fail.patch
mips-update_mmu_cache-can-replace-__update_tlb.patch
mips-update_mmu_cache-can-replace-__update_tlb-fix.patch
parisc-add-pte_unmap-to-balance-get_ptep.patch
parisc-unmap_uncached_pte-use-pte_offset_kernel.patch
parisc-hugetlb-pte_alloc_huge-pte_offset_huge.patch
powerpc-kvmppc_unmap_free_pmd-pte_offset_kernel.patch
powerpc-allow-pte_offset_map-to-fail.patch
powerpc-hugetlb-pte_alloc_huge.patch
riscv-hugetlb-pte_alloc_huge-pte_offset_huge.patch
s390-allow-pte_offset_map_lock-to-fail.patch
s390-gmap-use-pte_unmap_unlock-not-spin_unlock.patch
sh-hugetlb-pte_alloc_huge-pte_offset_huge.patch
sparc-hugetlb-pte_alloc_huge-pte_offset_huge.patch
sparc-allow-pte_offset_map-to-fail.patch
sparc-iounit-and-iommu-use-pte_offset_kernel.patch
x86-allow-get_locked_pte-to-fail.patch
x86-sme_populate_pgd-use-pte_offset_kernel.patch
xtensa-add-pte_unmap-to-balance-pte_offset_map.patch
mm-use-pmdp_get_lockless-without-surplus-barrier.patch
mm-migrate-remove-cruft-from-migration_entry_waits.patch
mm-pgtable-kmap_local_page-instead-of-kmap_atomic.patch
mm-pgtable-allow-pte_offset_map-to-fail.patch
mm-filemap-allow-pte_offset_map_lock-to-fail.patch
mm-page_vma_mapped-delete-bogosity-in-page_vma_mapped_walk.patch
mm-page_vma_mapped-reformat-map_pte-with-less-indentation.patch
mm-page_vma_mapped-pte_offset_map_nolock-not-pte_lockptr.patch
mm-pagewalkers-action_again-if-pte_offset_map_lock-fails.patch
mm-pagewalk-walk_pte_range-allow-for-pte_offset_map.patch
mm-vmwgfx-simplify-pmd-pud-mapping-dirty-helpers.patch
mm-vmalloc-vmalloc_to_page-use-pte_offset_kernel.patch
mm-hmm-retry-if-pte_offset_map-fails.patch
mm-userfaultfd-retry-if-pte_offset_map-fails.patch
mm-userfaultfd-allow-pte_offset_map_lock-to-fail.patch
mm-debug_vm_pgtablepage_table_check-warn-pte-map-fails.patch
mm-various-give-up-if-pte_offset_map-fails.patch
mm-mprotect-delete-pmd_none_or_clear_bad_unless_trans_huge.patch
mm-mremap-retry-if-either-pte_offset_map_lock-fails.patch
mm-madvise-clean-up-pte_offset_map_lock-scans.patch
mm-madvise-clean-up-force_shm_swapin_readahead.patch
mm-swapoff-allow-pte_offset_map-to-fail.patch
mm-mglru-allow-pte_offset_map_nolock-to-fail.patch
mm-migrate_device-allow-pte_offset_map_lock-to-fail.patch
mm-gup-remove-foll_split_pmd-use-of-pmd_trans_unstable.patch
mm-huge_memory-split-huge-pmd-under-one-pte_offset_map.patch
mm-khugepaged-allow-pte_offset_map-to-fail.patch
mm-memory-allow-pte_offset_map-to-fail.patch
mm-memory-handle_pte_fault-use-pte_offset_map_nolock.patch
mm-pgtable-delete-pmd_trans_unstable-and-friends.patch
mm-swap-swap_vma_readahead-do-the-pte_offset_map.patch
perf-core-allow-pte_offset_map-to-fail.patch
