Merge branch 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull timer fix from Thomas Gleixner:
 "A single fix for a ~10 years old problem which causes high resolution
  timers to stop after a CPU unplug/plug cycle due to a stale flag in
  the per CPU hrtimer base struct.

  Paul McKenney was hunting this for about a year, but the heisenbug
  nature made it resistant against debug attempts for quite some time"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  hrtimer: Reset hrtimer cpu base proper on CPU hotplug

1 files changed, 3 insertions, 0 deletions

diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index d32520840fde..aa9d2a2b1210 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -655,7 +655,9 @@ static void hrtimer_reprogram(struct hrtimer *timer,
 static inline void hrtimer_init_hres(struct hrtimer_cpu_base *base)
 {
         base->expires_next = KTIME_MAX;
+        base->hang_detected = 0;
         base->hres_active = 0;
+        base->next_timer = NULL;
 }
 
 /*
@@ -1589,6 +1591,7 @@ int hrtimers_prepare_cpu(unsigned int cpu)
                 timerqueue_init_head(&cpu_base->clock_base[i].active);
         }
 
+        cpu_base->active_bases = 0;
         cpu_base->cpu = cpu;
         hrtimer_init_hres(cpu_base);
         return 0;