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-rw-r--r--arch/x86/mm/fault.c13
1 files changed, 12 insertions, 1 deletions
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 29644175490..e4b9fc5001c 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -645,6 +645,7 @@ static noinline int spurious_fault(unsigned long error_code,
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
+ int ret;
/* Reserved-bit violation or user access to kernel space? */
if (error_code & (PF_USER | PF_RSVD))
@@ -672,7 +673,17 @@ static noinline int spurious_fault(unsigned long error_code,
if (!pte_present(*pte))
return 0;
- return spurious_fault_check(error_code, pte);
+ ret = spurious_fault_check(error_code, pte);
+ if (!ret)
+ return 0;
+
+ /*
+ * Make sure we have permissions in PMD
+ * If not, then there's a bug in the page tables.
+ */
+ ret = spurious_fault_check(error_code, (pte_t *) pmd);
+ WARN_ONCE(!ret, "PMD has incorrect permission bits\n");
+ return ret;
}
/*