Merge branch 'stable-3.2' into pandora-3.2

[pandora-kernel.git] / kernel / time / alarmtimer.c

diff --git a/kernel/time/alarmtimer.c b/kernel/time/alarmtimer.c
index a13a5dc..c82900c 100644 (file)
--- a/kernel/time/alarmtimer.c
+++ b/kernel/time/alarmtimer.c
@@ -419,7 +419,7 @@ u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval)
                overrun++;
        }
 
-       alarm->node.expires = ktime_add(alarm->node.expires, interval);
+       alarm->node.expires = ktime_add_safe(alarm->node.expires, interval);
        return overrun;
 }
 
@@ -448,18 +448,26 @@ static enum alarmtimer_type clock2alarm(clockid_t clockid)
 static enum alarmtimer_restart alarm_handle_timer(struct alarm *alarm,
                                                        ktime_t now)
 {
+       unsigned long flags;
        struct k_itimer *ptr = container_of(alarm, struct k_itimer,
                                                it.alarm.alarmtimer);
-       if (posix_timer_event(ptr, 0) != 0)
-               ptr->it_overrun++;
+       enum alarmtimer_restart result = ALARMTIMER_NORESTART;
+
+       spin_lock_irqsave(&ptr->it_lock, flags);
+       if ((ptr->it_sigev_notify & ~SIGEV_THREAD_ID) != SIGEV_NONE) {
+               if (posix_timer_event(ptr, 0) != 0)
+                       ptr->it_overrun++;
+       }
 
        /* Re-add periodic timers */
        if (ptr->it.alarm.interval.tv64) {
                ptr->it_overrun += alarm_forward(alarm, now,
                                                ptr->it.alarm.interval);
-               return ALARMTIMER_RESTART;
+               result = ALARMTIMER_RESTART;
        }
-       return ALARMTIMER_NORESTART;
+       spin_unlock_irqrestore(&ptr->it_lock, flags);
+
+       return result;
 }
 
 /**
@@ -590,13 +598,21 @@ static int alarm_timer_set(struct k_itimer *timr, int flags,
 
        /* start the timer */
        timr->it.alarm.interval = timespec_to_ktime(new_setting->it_interval);
+
+       /*
+        * Rate limit to the tick as a hot fix to prevent DOS. Will be
+        * mopped up later.
+        */
+       if (ktime_to_ns(timr->it.alarm.interval) < TICK_NSEC)
+               timr->it.alarm.interval = ktime_set(1, 0);
+
        exp = timespec_to_ktime(new_setting->it_value);
        /* Convert (if necessary) to absolute time */
        if (flags != TIMER_ABSTIME) {
                ktime_t now;
 
                now = alarm_bases[timr->it.alarm.alarmtimer.type].gettime();
-               exp = ktime_add(now, exp);
+               exp = ktime_add_safe(now, exp);
        }
 
        alarm_start(&timr->it.alarm.alarmtimer, exp);