Merge branch 'tip/x86/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into x86/mm

1 files changed, 12 insertions, 1 deletions

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 29644175490f..e4b9fc5001c6 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;
 }
 
 /*