[PATCH v3 11/17] x86: pgtable: move pagetable_dtor() to __tlb_remove_table()
From: Qi Zheng <hidden>
Date: 2024-12-23 09:45:24
Also in:
linux-arch, linux-arm-kernel, linux-m68k, linux-mips, linux-mm, linux-riscv, linux-s390, linux-sh, linux-um, lkml, loongarch, sparclinux
Subsystem:
mmu gather and tlb invalidation, paravirt_ops interface, the rest, x86 architecture (32-bit and 64-bit), x86 mm · Maintainers:
Will Deacon, "Aneesh Kumar K.V", Andrew Morton, Nick Piggin, Peter Zijlstra, Juergen Gross, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen, Andy Lutomirski
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. Signed-off-by: Qi Zheng <redacted> Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: x86@kernel.org --- 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(-)
diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index 73f0786181cc9..f64730be5ad67 100644
--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h@@ -31,24 +31,27 @@ static inline void tlb_flush(struct mmu_gather *tlb) */ 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 */
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 7bdcf152778c0..46d5d325483b0 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/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
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index a6cd9660e29ec..a0b0e501ba663 100644
--- a/arch/x86/mm/pgtable.c
+++ b/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 *tlb, struct page *pte) #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 *tlb, pmd_t *pmd) #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 *tlb, pud_t *pud) #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)); }
--
2.20.1