[PATCH] x86_64: Adjust page fault handling

Adjust page fault protection error check before considering it to be
a vmalloc synchronization candidate.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/arch/x86_64/mm/fault.c b/arch/x86_64/mm/fault.c
index 21d1596..fd07b86 100644 (file)
--- a/arch/x86_64/mm/fault.c
+++ b/arch/x86_64/mm/fault.c
@@ -299,7 +299,8 @@ int exception_trace = 1;
  *     bit 0 == 0 means no page found, 1 means protection fault
  *     bit 1 == 0 means read, 1 means write
  *     bit 2 == 0 means kernel, 1 means user-mode
- *      bit 3 == 1 means fault was an instruction fetch
+ *     bit 3 == 1 means use of reserved bit detected
+ *     bit 4 == 1 means fault was an instruction fetch
  */
 asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
                                        unsigned long error_code)
@@ -342,10 +343,10 @@ asmlinkage void __kprobes do_page_fault(struct pt_regs *regs,
         *
         * This verifies that the fault happens in kernel space
         * (error_code & 4) == 0, and that the fault was not a
-        * protection error (error_code & 1) == 0.
+        * protection error (error_code & 9) == 0.
         */
        if (unlikely(address >= TASK_SIZE64)) {
-               if (!(error_code & 5) &&
+               if (!(error_code & 0xd) &&
                      ((address >= VMALLOC_START && address < VMALLOC_END) ||
                       (address >= MODULES_VADDR && address < MODULES_END))) {
                        if (vmalloc_fault(address) < 0)