The patch titled
Subject: Revert "mm: pgtable: make ptlock be freed by RCU"
has been added to the -mm mm-unstable branch. Its filename is
revert-mm-pgtable-make-ptlock-be-freed-by-rcu.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/revert-mm-pgtable-make-ptlock-be-freed-by-rcu.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: Revert "mm: pgtable: make ptlock be freed by RCU"
Date: Mon, 23 Dec 2024 17:40:47 +0800
Patch series "move pagetable_*_dtor() to __tlb_remove_table()", v3.
As proposed by Peter Zijlstra[1], this patch series aims to move
pagetable_*_dtor() into __tlb_remove_table(). This will clean up
pagetable_*_dtor() a bit and more gracefully fix the UAF issue [2]
reported by syzbot.
[1]. https://lore.kernel.org/all/20241211133433.GC12500@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/
[2]. https://lore.kernel.org/all/67548279.050a0220.a30f1.015b.GAE@xxxxxxxxxx/
This patch (of 17):
This reverts commit 2f3443770437e49abc39af26962d293851cbab6d.
Link: https://lkml.kernel.org/r/cover.1734945104.git.zhengqi.arch@xxxxxxxxxxxxx
Link: https://lkml.kernel.org/r/b59adb960b2075822a6e57efc7a52e7eb7780068.1734945104.git.zhengqi.arch@xxxxxxxxxxxxx
Signed-off-by: Qi Zheng <zhengqi.arch@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: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
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>
---
include/linux/mm.h | 2 +-
include/linux/mm_types.h | 9 +--------
mm/memory.c | 22 ++++++----------------
3 files changed, 8 insertions(+), 25 deletions(-)
--- a/include/linux/mm.h~revert-mm-pgtable-make-ptlock-be-freed-by-rcu
+++ a/include/linux/mm.h
@@ -2925,7 +2925,7 @@ void ptlock_free(struct ptdesc *ptdesc);
static inline spinlock_t *ptlock_ptr(struct ptdesc *ptdesc)
{
- return &(ptdesc->ptl->ptl);
+ return ptdesc->ptl;
}
#else /* ALLOC_SPLIT_PTLOCKS */
static inline void ptlock_cache_init(void)
--- a/include/linux/mm_types.h~revert-mm-pgtable-make-ptlock-be-freed-by-rcu
+++ a/include/linux/mm_types.h
@@ -434,13 +434,6 @@ FOLIO_MATCH(flags, _flags_2a);
FOLIO_MATCH(compound_head, _head_2a);
#undef FOLIO_MATCH
-#if ALLOC_SPLIT_PTLOCKS
-struct pt_lock {
- spinlock_t ptl;
- struct rcu_head rcu;
-};
-#endif
-
/**
* struct ptdesc - Memory descriptor for page tables.
* @__page_flags: Same as page flags. Powerpc only.
@@ -489,7 +482,7 @@ struct ptdesc {
union {
unsigned long _pt_pad_2;
#if ALLOC_SPLIT_PTLOCKS
- struct pt_lock *ptl;
+ spinlock_t *ptl;
#else
spinlock_t ptl;
#endif
--- a/mm/memory.c~revert-mm-pgtable-make-ptlock-be-freed-by-rcu
+++ a/mm/memory.c
@@ -7014,34 +7014,24 @@ static struct kmem_cache *page_ptl_cache
void __init ptlock_cache_init(void)
{
- page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(struct pt_lock), 0,
+ page_ptl_cachep = kmem_cache_create("page->ptl", sizeof(spinlock_t), 0,
SLAB_PANIC, NULL);
}
bool ptlock_alloc(struct ptdesc *ptdesc)
{
- struct pt_lock *pt_lock;
+ spinlock_t *ptl;
- pt_lock = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
- if (!pt_lock)
+ ptl = kmem_cache_alloc(page_ptl_cachep, GFP_KERNEL);
+ if (!ptl)
return false;
- ptdesc->ptl = pt_lock;
+ ptdesc->ptl = ptl;
return true;
}
-static void ptlock_free_rcu(struct rcu_head *head)
-{
- struct pt_lock *pt_lock;
-
- pt_lock = container_of(head, struct pt_lock, rcu);
- kmem_cache_free(page_ptl_cachep, pt_lock);
-}
-
void ptlock_free(struct ptdesc *ptdesc)
{
- struct pt_lock *pt_lock = ptdesc->ptl;
-
- call_rcu(&pt_lock->rcu, ptlock_free_rcu);
+ kmem_cache_free(page_ptl_cachep, ptdesc->ptl);
}
#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-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
