[PATCH v5 12/17] x86: pgtable: move pagetable_dtor() to __tlb_remove_table()
From: Qi Zheng <hidden>
Date: 2025-01-08 07:02:22
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. Signed-off-by: Qi Zheng <redacted> Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Kevin Brodsky <redacted> Cc: x86@kernel.org --- arch/x86/include/asm/tlb.h | 1 + arch/x86/kernel/paravirt.c | 1 + arch/x86/mm/pgtable.c | 16 ++++------------ 3 files changed, 6 insertions(+), 12 deletions(-)
diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index 680ec3d47915a..f64730be5ad67 100644
--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h@@ -33,6 +33,7 @@ static inline void __tlb_remove_table(void *table) { struct ptdesc *ptdesc = (struct ptdesc *)table; + pagetable_dtor(ptdesc); pagetable_free(ptdesc); }
diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index dc1ab9301d2c6..1ccaa3397a670 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c@@ -64,6 +64,7 @@ static void native_tlb_remove_table(struct mmu_gather *tlb, void *table) { struct ptdesc *ptdesc = (struct ptdesc *)table; + pagetable_dtor(ptdesc); tlb_remove_page(tlb, ptdesc_page(ptdesc)); } #else
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index f9516024cbe5d..c02aa0427a6a5 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c@@ -25,6 +25,7 @@ void paravirt_tlb_remove_table(struct mmu_gather *tlb, void *table) { struct ptdesc *ptdesc = (struct ptdesc *)table; + pagetable_dtor(ptdesc); tlb_remove_page(tlb, ptdesc_page(ptdesc)); } #else
@@ -62,7 +63,6 @@ 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, page_ptdesc(pte)); }
@@ -70,7 +70,6 @@ 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
@@ -79,28 +78,21 @@ 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); + paravirt_tlb_remove_table(tlb, virt_to_ptdesc(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, ptdesc); + paravirt_tlb_remove_table(tlb, virt_to_ptdesc(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, ptdesc); + paravirt_tlb_remove_table(tlb, virt_to_ptdesc(p4d)); } #endif /* CONFIG_PGTABLE_LEVELS > 4 */ #endif /* CONFIG_PGTABLE_LEVELS > 3 */
--
2.20.1