x86: 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.

Link: https://lkml.kernel.org/r/27b3cdc8786bebd4f748380bf82f796482718504.1736317725.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>
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: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index 680ec3d47915a1a9d94063b69e7eba026eede961..f64730be5ad679cecf58f4a0740641732d78c4f9 100644 (file)
--- 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 e9bd0ba2d453f831856e6b639ef9a7033a495c8c..70161999c9737a51bf3bd1cefb028669edb42382 100644 (file)
--- 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 f9516024cbe5d26dcccc26cbb1d38527306cafa7..c02aa0427a6a59f113d637ad47359cdb6ba7c006 100644 (file)
--- 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 */