2 files changed, 11 insertions, 9 deletions

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index c027d4f602f1..e4c699dfa4e8 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -182,7 +182,10 @@ void clockevents_register_device(struct clock_event_device *dev)
         unsigned long flags;
 
         BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
-        BUG_ON(!dev->cpumask);
+        if (!dev->cpumask) {
+                WARN_ON(num_possible_cpus() > 1);
+                dev->cpumask = cpumask_of(smp_processor_id());
+        }
 
         raw_spin_lock_irqsave(&clockevents_lock, flags);
 
diff --git a/kernel/timer.c b/kernel/timer.c
index fd6198692b57..8cff36119e4d 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -749,16 +749,15 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
         unsigned long expires_limit, mask;
         int bit;
 
-        expires_limit = expires;
-
         if (timer->slack >= 0) {
                 expires_limit = expires + timer->slack;
         } else {
-                unsigned long now = jiffies;
+                long delta = expires - jiffies;
+
+                if (delta < 256)
+                        return expires;
 
-                /* No slack, if already expired else auto slack 0.4% */
-                if (time_after(expires, now))
-                        expires_limit = expires + (expires - now)/256;
+                expires_limit = expires + delta / 256;
         }
         mask = expires ^ expires_limit;
         if (mask == 0)
@@ -795,6 +794,8 @@ unsigned long apply_slack(struct timer_list *timer, unsigned long expires)
  */
 int mod_timer(struct timer_list *timer, unsigned long expires)
 {
+        expires = apply_slack(timer, expires);
+
         /*
          * This is a common optimization triggered by the
          * networking code - if the timer is re-modified
@@ -803,8 +804,6 @@ int mod_timer(struct timer_list *timer, unsigned long expires)
         if (timer_pending(timer) && timer->expires == expires)
                 return 1;
 
-        expires = apply_slack(timer, expires);
-
         return __mod_timer(timer, expires, false, TIMER_NOT_PINNED);
 }
 EXPORT_SYMBOL(mod_timer);