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: Mon, 23 Dec 2024 17:40:57 +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/0dc5a3bf5a692e24379c1d3b879a6d4396f0dbbd.1734945104.git.zhengqi.arch@xxxxxxxxxxxxx
Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
Suggested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
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: Kevin Brodsky <kevin.brodsky@xxxxxxx>
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: 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 | 17 ++++++++++-------
arch/x86/kernel/paravirt.c | 1 +
arch/x86/mm/pgtable.c | 12 ++----------
3 files changed, 13 insertions(+), 17 deletions(-)
--- a/arch/x86/include/asm/tlb.h~x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/x86/include/asm/tlb.h
@@ -31,24 +31,27 @@ static inline void tlb_flush(struct mmu_
*/
static inline void __tlb_remove_table(void *table)
{
- free_page_and_swap_cache(table);
+ struct ptdesc *ptdesc = (struct ptdesc *)table;
+
+ pagetable_dtor(ptdesc);
+ pagetable_free(ptdesc);
}
#ifdef CONFIG_PT_RECLAIM
static inline void __tlb_remove_table_one_rcu(struct rcu_head *head)
{
- struct page *page;
+ struct ptdesc *ptdesc;
- page = container_of(head, struct page, rcu_head);
- put_page(page);
+ ptdesc = container_of(head, struct ptdesc, pt_rcu_head);
+ __tlb_remove_table(ptdesc);
}
static inline void __tlb_remove_table_one(void *table)
{
- struct page *page;
+ struct ptdesc *ptdesc;
- page = table;
- call_rcu(&page->rcu_head, __tlb_remove_table_one_rcu);
+ ptdesc = table;
+ call_rcu(&ptdesc->pt_rcu_head, __tlb_remove_table_one_rcu);
}
#define __tlb_remove_table_one __tlb_remove_table_one
#endif /* CONFIG_PT_RECLAIM */
--- a/arch/x86/kernel/paravirt.c~x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/x86/kernel/paravirt.c
@@ -62,6 +62,7 @@ void __init native_pv_lock_init(void)
#ifndef CONFIG_PT_RECLAIM
static void native_tlb_remove_table(struct mmu_gather *tlb, void *table)
{
+ pagetable_dtor(table);
tlb_remove_page(tlb, table);
}
#else
--- a/arch/x86/mm/pgtable.c~x86-pgtable-move-pagetable_dtor-to-__tlb_remove_table
+++ a/arch/x86/mm/pgtable.c
@@ -23,6 +23,7 @@ EXPORT_SYMBOL(physical_mask);
static inline
void paravirt_tlb_remove_table(struct mmu_gather *tlb, void *table)
{
+ pagetable_dtor(table);
tlb_remove_page(tlb, table);
}
#else
@@ -60,7 +61,6 @@ 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, pte);
}
@@ -68,7 +68,6 @@ 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
@@ -77,16 +76,12 @@ 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_page(ptdesc));
+ paravirt_tlb_remove_table(tlb, virt_to_page(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, virt_to_page(pud));
}
@@ -94,9 +89,6 @@ void ___pud_free_tlb(struct mmu_gather *
#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, virt_to_page(p4d));
}
_
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-move-pagetable_dtor-to-__tlb_remove_table.patch
s390-pgtable-also-move-pagetable_dtor-of-pxd-to-__tlb_remove_table.patch
mm-pgtable-introduce-generic-__tlb_remove_table.patch
mm-pgtable-move-__tlb_remove_table_one-in-x86-to-generic-file.patch
mm-pgtable-remove-tlb_remove_page_ptdesc.patch
mm-pgtable-remove-tlb_remove_ptdesc.patch
mm-pgtable-introduce-generic-pagetable_dtor_free.patch
