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-rw-r--r--mm/pagewalk.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index 64437105fe0d..2022333805d3 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -48,8 +48,11 @@ static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
if (walk->no_vma) {
/*
* pte_offset_map() might apply user-specific validation.
+ * Indeed, on x86_64 the pmd entries set up by init_espfix_ap()
+ * fit its pmd_bad() check (_PAGE_NX set and _PAGE_RW clear),
+ * and CONFIG_EFI_PGT_DUMP efi_mm goes so far as to walk them.
*/
- if (walk->mm == &init_mm)
+ if (walk->mm == &init_mm || addr >= TASK_SIZE)
pte = pte_offset_kernel(pmd, addr);
else
pte = pte_offset_map(pmd, addr);