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Commit 4339e3f3 authored by Steve Capper's avatar Steve Capper Committed by Catalin Marinas
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arm64: mm: Correct show_pte behaviour 



show_pte makes use of the *_none_or_clear_bad style functions. If a
pgd, pud or pmd is identified as being bad, it will then be cleared.

As show_pte appears to be called from either the user or kernel
fault handlers this side effect can lead to unpredictable behaviour;
especially as TLB entries are not invalidated.

This patch removes the page table sanitisation from show_pte. If a
bad pgd, pud or pmd is encountered it is left unmodified.

Signed-off-by: default avatarSteve Capper <steve.capper@linaro.org>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent f15a2a12

arch/arm64/mm/fault.c

+3 −3
Original line number Diff line number Diff line
@@ -57,16 +57,16 @@ void show_pte(struct mm_struct *mm, unsigned long addr) 
		pmd_t *pmd;

		pte_t *pte;



		if (pgd_none_or_clear_bad(pgd))

		if (pgd_none(*pgd) || pgd_bad(*pgd))

			break;



		pud = pud_offset(pgd, addr);

		if (pud_none_or_clear_bad(pud))

		if (pud_none(*pud) || pud_bad(*pud))

			break;



		pmd = pmd_offset(pud, addr);

		printk(", *pmd=%016llx", pmd_val(*pmd));

		if (pmd_none_or_clear_bad(pmd))

		if (pmd_none(*pmd) || pmd_bad(*pmd))

			break;



		pte = pte_offset_map(pmd, addr);