Commit 12359c03 authored Jan 08, 2025 by Qi Zheng Committed by Andrew Morton Jan 25, 2025

arm64: pgtable: move pagetable_dtor() to __tlb_remove_table()

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/cf4b847caf390f96a3e3d534dacb2c174e16c154.1736317725.git.zhengqi.arch@bytedance.com


Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kevin Brodsky <kevin.brodsky@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
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: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 0ada8c4d

arch/arm64/include/asm/tlb.h

+4 −6

Original line number	Diff line number	Diff line
		@@ -9,11 +9,13 @@
		#define __ASM_TLB_H

		#include <linux/pagemap.h>
		#include <linux/swap.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);
		}

		#define tlb_flush tlb_flush
		@@ -82,7 +84,6 @@ static inline void __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte,
		{
		struct ptdesc *ptdesc = page_ptdesc(pte);

		pagetable_dtor(ptdesc);
		tlb_remove_ptdesc(tlb, ptdesc);
		}

		@@ -92,7 +93,6 @@ static inline void __pmd_free_tlb(struct mmu_gather tlb, pmd_t pmdp,
		{
		struct ptdesc *ptdesc = virt_to_ptdesc(pmdp);

		pagetable_dtor(ptdesc);
		tlb_remove_ptdesc(tlb, ptdesc);
		}
		#endif
		@@ -106,7 +106,6 @@ static inline void __pud_free_tlb(struct mmu_gather tlb, pud_t pudp,
		if (!pgtable_l4_enabled())
		return;

		pagetable_dtor(ptdesc);
		tlb_remove_ptdesc(tlb, ptdesc);
		}
		#endif
		@@ -120,7 +119,6 @@ static inline void __p4d_free_tlb(struct mmu_gather tlb, p4d_t p4dp,
		if (!pgtable_l5_enabled())
		return;

		pagetable_dtor(ptdesc);
		tlb_remove_ptdesc(tlb, ptdesc);
		}
		#endif