The patch titled
Subject: x86: pgtable: move pagetable_dtor() to __tlb_remove_table()
has been added to the -mm mm-unstable branch. Its filename is
x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table.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: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Subject: x86: pgtable: move pagetable_dtor() to __tlb_remove_table()
Date: Wed, 8 Jan 2025 14:57:28 +0800
Move pagetable_dtor() to __tlb_remove_table(), so that ptlock and page
table pages can be freed together (regardless of whether RCU is used).
This prevents the use-after-free problem where the ptlock is freed
immediately but the page table pages is freed later via RCU.
Link: https://lkml.kernel.org/r/27b3cdc8786bebd4f748380bf82f796482718504.1736317725.git.zhengqi.arch@xxxxxxxxxxxxx
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Suggested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Kevin Brodsky <kevin.brodsky@xxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Alexandre Ghiti <alex@xxxxxxxx>
Cc: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Cc: Andreas Larsson <andreas@xxxxxxxxxxx>
Cc: Aneesh Kumar K.V (Arm) <aneesh.kumar@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mike Rapoport (Microsoft) <rppt@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/tlb.h | 1 +
arch/x86/kernel/paravirt.c | 1 +
arch/x86/mm/pgtable.c | 16 ++++------------
3 files changed, 6 insertions(+), 12 deletions(-)
--- a/arch/x86/include/asm/tlb.h~x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/x86/include/asm/tlb.h
@@ -33,6 +33,7 @@ static inline void __tlb_remove_table(vo
{
struct ptdesc *ptdesc = (struct ptdesc *)table;
+ pagetable_dtor(ptdesc);
pagetable_free(ptdesc);
}
--- a/arch/x86/kernel/paravirt.c~x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/x86/kernel/paravirt.c
@@ -64,6 +64,7 @@ static void native_tlb_remove_table(stru
{
struct ptdesc *ptdesc = (struct ptdesc *)table;
+ pagetable_dtor(ptdesc);
tlb_remove_page(tlb, ptdesc_page(ptdesc));
}
#else
--- a/arch/x86/mm/pgtable.c~x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/x86/mm/pgtable.c
@@ -25,6 +25,7 @@ void paravirt_tlb_remove_table(struct mm
{
struct ptdesc *ptdesc = (struct ptdesc *)table;
+ pagetable_dtor(ptdesc);
tlb_remove_page(tlb, ptdesc_page(ptdesc));
}
#else
@@ -62,7 +63,6 @@ early_param("userpte", setup_userpte);
void ___pte_free_tlb(struct mmu_gather *tlb, struct page *pte)
{
- pagetable_dtor(page_ptdesc(pte));
paravirt_release_pte(page_to_pfn(pte));
paravirt_tlb_remove_table(tlb, page_ptdesc(pte));
}
@@ -70,7 +70,6 @@ void ___pte_free_tlb(struct mmu_gather *
#if CONFIG_PGTABLE_LEVELS > 2
void ___pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmd)
{
- struct ptdesc *ptdesc = virt_to_ptdesc(pmd);
paravirt_release_pmd(__pa(pmd) >> PAGE_SHIFT);
/*
* NOTE! For PAE, any changes to the top page-directory-pointer-table
@@ -79,28 +78,21 @@ void ___pmd_free_tlb(struct mmu_gather *
#ifdef CONFIG_X86_PAE
tlb->need_flush_all = 1;
#endif
- pagetable_dtor(ptdesc);
- paravirt_tlb_remove_table(tlb, ptdesc);
+ paravirt_tlb_remove_table(tlb, virt_to_ptdesc(pmd));
}
#if CONFIG_PGTABLE_LEVELS > 3
void ___pud_free_tlb(struct mmu_gather *tlb, pud_t *pud)
{
- struct ptdesc *ptdesc = virt_to_ptdesc(pud);
-
- pagetable_dtor(ptdesc);
paravirt_release_pud(__pa(pud) >> PAGE_SHIFT);
- paravirt_tlb_remove_table(tlb, ptdesc);
+ paravirt_tlb_remove_table(tlb, virt_to_ptdesc(pud));
}
#if CONFIG_PGTABLE_LEVELS > 4
void ___p4d_free_tlb(struct mmu_gather *tlb, p4d_t *p4d)
{
- struct ptdesc *ptdesc = virt_to_ptdesc(p4d);
-
- pagetable_dtor(ptdesc);
paravirt_release_p4d(__pa(p4d) >> PAGE_SHIFT);
- paravirt_tlb_remove_table(tlb, ptdesc);
+ paravirt_tlb_remove_table(tlb, virt_to_ptdesc(p4d));
}
#endif /* CONFIG_PGTABLE_LEVELS > 4 */
#endif /* CONFIG_PGTABLE_LEVELS > 3 */
_
Patches currently in -mm which might be from zhengqi.arch@xxxxxxxxxxxxx are
mm-pgtable-make-ptep_clear-non-atomic.patch
mm-khugepaged-recheck-pmd-state-in-retract_page_tables.patch
mm-userfaultfd-recheck-dst_pmd-entry-in-move_pages_pte.patch
mm-userfaultfd-recheck-dst_pmd-entry-in-move_pages_pte-fix.patch
mm-introduce-zap_nonpresent_ptes.patch
mm-introduce-do_zap_pte_range.patch
mm-skip-over-all-consecutive-none-ptes-in-do_zap_pte_range.patch
mm-zap_install_uffd_wp_if_needed-return-whether-uffd-wp-pte-has-been-re-installed.patch
mm-do_zap_pte_range-return-any_skipped-information-to-the-caller.patch
mm-make-zap_pte_range-handle-full-within-pmd-range.patch
mm-pgtable-reclaim-empty-pte-page-in-madvisemadv_dontneed.patch
mm-pgtable-reclaim-empty-pte-page-in-madvisemadv_dontneed-fix.patch
x86-mm-free-page-table-pages-by-rcu-instead-of-semi-rcu.patch
mm-pgtable-make-ptlock-be-freed-by-rcu.patch
x86-select-arch_supports_pt_reclaim-if-x86_64.patch
revert-mm-pgtable-make-ptlock-be-freed-by-rcu.patch
mm-pgtable-add-statistics-for-p4d-level-page-table.patch
arm64-pgtable-use-mmu-gather-to-free-p4d-level-page-table.patch
s390-pgtable-add-statistics-for-pud-and-p4d-level-page-table.patch
mm-pgtable-introduce-pagetable_dtor.patch
arm-pgtable-move-pagetable_dtor-to-__tlb_remove_table.patch
arm64-pgtable-move-pagetable_dtor-to-__tlb_remove_table.patch
riscv-pgtable-move-pagetable_dtor-to-__tlb_remove_table.patch
x86-pgtable-convert-__tlb_remove_table-to-use-struct-ptdesc.patch
x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table.patch
s390-pgtable-consolidate-pxd-and-pte-tlb-free-paths.patch
mm-pgtable-introduce-generic-__tlb_remove_table.patch
mm-pgtable-completely-move-pagetable_dtor-to-generic-tlb_remove_table.patch
mm-pgtable-move-__tlb_remove_table_one-in-x86-to-generic-file.patch
mm-pgtable-introduce-generic-pagetable_dtor_free.patch
