From: Lai Jiangshan <la...@linux.alibaba.com>
All callers don't call pti_clone_pagetable() on range that
includes pud large page(1G). If it were called in such
case, there would be bugs in the caller size, so it worth
a warning for robustness.
Also add check for pgd_large() & p4d_large() with the same
reason, and pgd_large() & p4d_large() are constant 0 which
just acts as self-comment in code without overhead.
Signed-off-by: Lai Jiangshan <la...@linux.alibaba.com>
---
arch/x86/mm/pti.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index a229320515da..89366fec956b 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -321,10 +321,10 @@ pti_clone_pgtable(unsigned long start, unsigned long end,
break;
pgd = pgd_offset_k(addr);
- if (WARN_ON(pgd_none(*pgd)))
+ if (WARN_ON(pgd_none(*pgd) || pgd_large(*pgd)))
return;
p4d = p4d_offset(pgd, addr);
- if (WARN_ON(p4d_none(*p4d)))
+ if (WARN_ON(p4d_none(*p4d) || p4d_large(*p4d)))
return;
pud = pud_offset(p4d, addr);
@@ -333,6 +333,8 @@ pti_clone_pgtable(unsigned long start, unsigned long end,
addr = round_up(addr + 1, PUD_SIZE);
continue;
}
+ if (WARN_ON(pud_large(*pud)))
+ return;
pmd = pmd_offset(pud, addr);
if (pmd_none(*pmd)) {
--
2.19.1.6.gb485710b
