diff options
| author | Qi Zheng <zhengqi.arch@bytedance.com> | 2025-01-08 09:57:23 +0300 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2025-01-26 07:22:22 +0300 |
| commit | db6b435d731a8d82c38e558175db55466cb5832a (patch) | |
| tree | 6ad4b763d825245c7cd99ae9af18fb8c2fc29e13 /Documentation/mm | |
| parent | b7dcd539bfc7301b56fdaa6ebbb23752b670ee81 (diff) | |
| download | linux-db6b435d731a8d82c38e558175db55466cb5832a.tar.xz | |
mm: pgtable: introduce pagetable_dtor()
The pagetable_p*_dtor() are exactly the same except for the handling of
ptlock. If we make ptlock_free() handle the case where ptdesc->ptl is
NULL and remove VM_BUG_ON_PAGE() from pmd_ptlock_free(), we can unify
pagetable_p*_dtor() into one function. Let's introduce pagetable_dtor()
to do this.
Later, pagetable_dtor() will be moved to tlb_remove_ptdesc(), 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/47f44fff9dc68d9d9e9a0d6c036df275f820598a.1736317725.git.zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Originally-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com> [s390]
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Alexandre Ghiti <alexghiti@rivosinc.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jann Horn <jannh@google.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'Documentation/mm')
| -rw-r--r-- | Documentation/mm/split_page_table_lock.rst | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/Documentation/mm/split_page_table_lock.rst b/Documentation/mm/split_page_table_lock.rst index 581446d4a4eb..8e1ceb0a6619 100644 --- a/Documentation/mm/split_page_table_lock.rst +++ b/Documentation/mm/split_page_table_lock.rst @@ -62,7 +62,7 @@ Support of split page table lock by an architecture =================================================== There's no need in special enabling of PTE split page table lock: everything -required is done by pagetable_pte_ctor() and pagetable_pte_dtor(), which +required is done by pagetable_pte_ctor() and pagetable_dtor(), which must be called on PTE table allocation / freeing. Make sure the architecture doesn't use slab allocator for page table @@ -73,7 +73,7 @@ PMD split lock only makes sense if you have more than two page table levels. PMD split lock enabling requires pagetable_pmd_ctor() call on PMD table -allocation and pagetable_pmd_dtor() on freeing. +allocation and pagetable_dtor() on freeing. Allocation usually happens in pmd_alloc_one(), freeing in pmd_free() and pmd_free_tlb(), but make sure you cover all PMD table allocation / freeing |