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Commit f02ab08a authored by Punit Agrawal's avatar Punit Agrawal Committed by Will Deacon
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arm64: hugetlb: Fix huge_pte_offset to return poisoned page table entries 



When memory failure is enabled, a poisoned hugepage pte is marked as a
swap entry. huge_pte_offset() does not return the poisoned page table
entries when it encounters PUD/PMD hugepages.

This behaviour of huge_pte_offset() leads to error such as below when
munmap is called on poisoned hugepages.

[  344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074.

Fix huge_pte_offset() to return the poisoned pte which is then
appropriately handled by the generic layer code.

Signed-off-by: default avatarPunit Agrawal <punit.agrawal@arm.com>
Acked-by: default avatarSteve Capper <steve.capper@arm.com>
Reviewed-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
Cc: David Woods <dwoods@mellanox.com>
Tested-by: default avatarManoj Iyer <manoj.iyer@canonical.com>
Signed-off-by: default avatarWill Deacon <will.deacon@arm.com>
parent 68764420

arch/arm64/include/asm/pgtable.h

+1 −1
Original line number Diff line number Diff line
@@ -441,7 +441,7 @@ static inline phys_addr_t pmd_page_paddr(pmd_t pmd) 


#define pud_none(pud)		(!pud_val(pud))

#define pud_bad(pud)		(!(pud_val(pud) & PUD_TABLE_BIT))

#define pud_present(pud)	(pud_val(pud))

#define pud_present(pud)	pte_present(pud_pte(pud))



static inline void set_pud(pud_t *pudp, pud_t pud)

{

arch/arm64/mm/hugetlbpage.c

+10 −19
Original line number Diff line number Diff line
@@ -136,36 +136,27 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 
{

	pgd_t *pgd;

	pud_t *pud;

	pmd_t *pmd = NULL;

	pte_t *pte = NULL;

	pmd_t *pmd;



	pgd = pgd_offset(mm, addr);

	pr_debug("%s: addr:0x%lx pgd:%p\n", __func__, addr, pgd);

	if (!pgd_present(*pgd))

		return NULL;



	pud = pud_offset(pgd, addr);

	if (!pud_present(*pud))

	if (pud_none(*pud))

		return NULL;



	if (pud_huge(*pud))

	/* swap or huge page */

	if (!pud_present(*pud) || pud_huge(*pud))

		return (pte_t *)pud;

	/* table; check the next level */



	pmd = pmd_offset(pud, addr);

	if (!pmd_present(*pmd))

	if (pmd_none(*pmd))

		return NULL;



	if (pte_cont(pmd_pte(*pmd))) {

		pmd = pmd_offset(

			pud, (addr & CONT_PMD_MASK));

	if (!pmd_present(*pmd) || pmd_huge(*pmd))

		return (pte_t *)pmd;

	}

	if (pmd_huge(*pmd))

		return (pte_t *)pmd;

	pte = pte_offset_kernel(pmd, addr);

	if (pte_present(*pte) && pte_cont(*pte)) {

		pte = pte_offset_kernel(

			pmd, (addr & CONT_PTE_MASK));

		return pte;

	}



	return NULL;

}