x86/mce: Fix siginfo_t->si_addr value for non-recoverable memory faults

In commit dad1743e5993f1 ("x86/mce: Only restart instruction after machine
check recovery if it is safe") we fixed mce_notify_process() to force a
signal to the current process if it was not restartable (RIPV bit not
set in MCG_STATUS). But doing it here means that the process doesn't
get told the virtual address of the fault via siginfo_t->si_addr. This
would prevent application level recovery from the fault.

Make a new MF_MUST_KILL flag bit for memory_failure() et al. to use so
that we will provide the right information with the signal.

Signed-off-by: Tony Luck <tony.luck@intel.com>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Cc: stable@kernel.org    # 3.4+

1 files changed, 4 insertions, 2 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index da27c5d2168a..c46ed494f002 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -1186,6 +1186,7 @@ void mce_notify_process(void)
 {
         unsigned long pfn;
         struct mce_info *mi = mce_find_info();
+        int flags = MF_ACTION_REQUIRED;
 
         if (!mi)
                 mce_panic("Lost physical address for unconsumed uncorrectable error", NULL, NULL);
@@ -1200,8 +1201,9 @@ void mce_notify_process(void)
          * doomed. We still need to mark the page as poisoned and alert any
          * other users of the page.
          */
-        if (memory_failure(pfn, MCE_VECTOR, MF_ACTION_REQUIRED) < 0 ||
-                           mi->restartable == 0) {
+        if (!mi->restartable)
+                flags |= MF_MUST_KILL;
+        if (memory_failure(pfn, MCE_VECTOR, flags) < 0) {
                 pr_err("Memory error not recovered");
                 force_sig(SIGBUS, current);
         }