Commit 0ada8c4d authored by Qi Zheng's avatar Qi Zheng Committed by Andrew Morton
Browse files

arm: 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/327b4b8990729edd4ce97d9d5acbdaff2d9fa1d1.1736317725.git.zhengqi.arch@bytedance.com


Signed-off-by: default avatarQi Zheng <zhengqi.arch@bytedance.com>
Suggested-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarKevin 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: default avatarAndrew Morton <akpm@linux-foundation.org>
parent db6b435d

arch/arm/include/asm/tlb.h

+6 −3
Original line number Diff line number Diff line
@@ -26,12 +26,14 @@ 


#else /* !CONFIG_MMU */



#include <linux/swap.h>

#include <asm/tlbflush.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);

}



#include <asm-generic/tlb.h>
@@ -41,7 +43,9 @@ __pte_free_tlb(struct mmu_gather *tlb, pgtable_t pte, unsigned long addr) 
{

	struct ptdesc *ptdesc = page_ptdesc(pte);



#ifndef CONFIG_MMU_GATHER_TABLE_FREE

	pagetable_dtor(ptdesc);

#endif



#ifndef CONFIG_ARM_LPAE

	/*
@@ -61,7 +65,6 @@ __pmd_free_tlb(struct mmu_gather *tlb, pmd_t *pmdp, unsigned long addr) 
#ifdef CONFIG_ARM_LPAE

	struct ptdesc *ptdesc = virt_to_ptdesc(pmdp);



	pagetable_dtor(ptdesc);

	tlb_remove_ptdesc(tlb, ptdesc);

#endif

}