3 files changed, 19 insertions, 4 deletions

diff --git a/kernel/time/clockevents.c b/kernel/time/clockevents.c
index 6f740d9f0948..d7395fdfb9f3 100644
--- a/kernel/time/clockevents.c
+++ b/kernel/time/clockevents.c
@@ -259,7 +259,8 @@ void clockevents_notify(unsigned long reason, void *arg)
                 cpu = *((int *)arg);
                 list_for_each_entry_safe(dev, tmp, &clockevent_devices, list) {
                         if (cpumask_test_cpu(cpu, dev->cpumask) &&
-                            cpumask_weight(dev->cpumask) == 1) {
+                            cpumask_weight(dev->cpumask) == 1 &&
+                            !tick_is_broadcast_device(dev)) {
                                 BUG_ON(dev->mode != CLOCK_EVT_MODE_UNUSED);
                                 list_del(&dev->list);
                         }
diff --git a/kernel/time/clocksource.c b/kernel/time/clocksource.c
index e85c23404d34..13700833c181 100644
--- a/kernel/time/clocksource.c
+++ b/kernel/time/clocksource.c
@@ -343,7 +343,19 @@ static void clocksource_resume_watchdog(void)
 {
         unsigned long flags;
 
-        spin_lock_irqsave(&watchdog_lock, flags);
+        /*
+         * We use trylock here to avoid a potential dead lock when
+         * kgdb calls this code after the kernel has been stopped with
+         * watchdog_lock held. When watchdog_lock is held we just
+         * return and accept, that the watchdog might trigger and mark
+         * the monitored clock source (usually TSC) unstable.
+         *
+         * This does not affect the other caller clocksource_resume()
+         * because at this point the kernel is UP, interrupts are
+         * disabled and nothing can hold watchdog_lock.
+         */
+        if (!spin_trylock_irqsave(&watchdog_lock, flags))
+                return;
         clocksource_reset_watchdog();
         spin_unlock_irqrestore(&watchdog_lock, flags);
 }
@@ -458,8 +470,8 @@ void clocksource_resume(void)
  * clocksource_touch_watchdog - Update watchdog
  *
  * Update the watchdog after exception contexts such as kgdb so as not
- * to incorrectly trip the watchdog.
- *
+ * to incorrectly trip the watchdog. This might fail when the kernel
+ * was stopped in code which holds watchdog_lock.
  */
 void clocksource_touch_watchdog(void)
 {
diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c
index 7faaa32fbf4f..e2ab064c6d41 100644
--- a/kernel/time/timekeeping.c
+++ b/kernel/time/timekeeping.c
@@ -880,6 +880,7 @@ void getboottime(struct timespec *ts)
 
         set_normalized_timespec(ts, -boottime.tv_sec, -boottime.tv_nsec);
 }
+EXPORT_SYMBOL_GPL(getboottime);
 
 /**
  * monotonic_to_bootbased - Convert the monotonic time to boot based.
@@ -889,6 +890,7 @@ void monotonic_to_bootbased(struct timespec *ts)
 {
         *ts = timespec_add_safe(*ts, total_sleep_time);
 }
+EXPORT_SYMBOL_GPL(monotonic_to_bootbased);
 
 unsigned long get_seconds(void)
 {