The patch titled
Subject: arm: pgtable: move pagetable_dtor() to __tlb_remove_table()
has been added to the -mm mm-unstable branch. Its filename is
arm-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/arm-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: arm: pgtable: move pagetable_dtor() to __tlb_remove_table()
Date: Wed, 8 Jan 2025 14:57:24 +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.
Page tables shouldn't have swap cache, so use pagetable_free() instead of
free_page_and_swap_cache() to free page table pages.
Link: https://lkml.kernel.org/r/327b4b8990729edd4ce97d9d5acbdaff2d9fa1d1.1736317725.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/arm/include/asm/tlb.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/arm/include/asm/tlb.h~arm-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/arm/include/asm/tlb.h
@@ -26,12 +26,14 @@
#else /* !CONFIG_MMU */
-#include <linux/swap.h>
#include <asm/tlbflush.h>
static inline void __tlb_remove_table(void *_table)
{
- free_page_and_swap_cache((struct page *)_table);
+ struct ptdesc *ptdesc = (struct ptdesc *)_table;
+
+ pagetable_dtor(ptdesc);
+ pagetable_free(ptdesc);
}
#include <asm-generic/tlb.h>
@@ -41,7 +43,9 @@ __pte_free_tlb(struct mmu_gather *tlb, p
{
struct ptdesc *ptdesc = page_ptdesc(pte);
+#ifndef CONFIG_MMU_GATHER_TABLE_FREE
pagetable_dtor(ptdesc);
+#endif
#ifndef CONFIG_ARM_LPAE
/*
@@ -61,7 +65,6 @@ __pmd_free_tlb(struct mmu_gather *tlb, p
#ifdef CONFIG_ARM_LPAE
struct ptdesc *ptdesc = virt_to_ptdesc(pmdp);
- pagetable_dtor(ptdesc);
tlb_remove_ptdesc(tlb, ptdesc);
#endif
}
_
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
