huge_pte_offset() does not correctly handle poisoned or migration page
table entries. It returns NULL instead of the offset when it encounters
a swap entry. This leads to errors such as
[ 344.165544] mm/pgtable-generic.c:33: bad pmd 000000083af00074.
in the kernel log when unmapping memory on process exit.
huge_pte_offset() is now provided with the size of the hugepage being
accessed. Use the size to find the correct page table entry to return.
Signed-off-by: Punit Agrawal <punit.agrawal@xxxxxxx>
Cc: David Woods <dwoods@xxxxxxxxxxxx>
---
arch/arm64/mm/hugetlbpage.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index 1bc08ae49e6a..009648c4500f 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -194,36 +194,36 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
{
pgd_t *pgd;
pud_t *pud;
- pmd_t *pmd = NULL;
- pte_t *pte = NULL;
+ pmd_t *pmd;
+ pte_t *pte;
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) && sz != PUD_SIZE)
return NULL;
-
- if (pud_huge(*pud))
+ else if (!pud_table(*pud))
return (pte_t *)pud;
+
+ if (sz == CONT_PMD_SIZE)
+ addr &= CONT_PMD_MASK;
+
pmd = pmd_offset(pud, addr);
- if (!pmd_present(*pmd))
+ if (pmd_none(*pmd) &&
+ !(sz == PMD_SIZE || sz == CONT_PMD_SIZE))
return NULL;
-
- if (pte_cont(pmd_pte(*pmd))) {
- pmd = pmd_offset(
- pud, (addr & CONT_PMD_MASK));
- return (pte_t *)pmd;
- }
- if (pmd_huge(*pmd))
+ else if (!pmd_table(*pmd))
return (pte_t *)pmd;
- pte = pte_offset_kernel(pmd, addr);
- if (pte_present(*pte) && pte_cont(*pte)) {
+
+ if (sz == CONT_PTE_SIZE) {
pte = pte_offset_kernel(
pmd, (addr & CONT_PTE_MASK));
return pte;
}
+
return NULL;
}
--
2.11.0
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