diff options
authorJeff Ohlstein <>2011-11-18 15:47:10 -0800
committerGreg Kroah-Hartman <>2011-12-09 08:54:23 -0800
commiteb5f9ebf61f88796a19df09751762b9e086a5214 (patch)
parent92ad5083db212ff3c5f6d1d085d85790f7a6c42c (diff)
hrtimer: Fix extra wakeups from __remove_hrtimer()
commit 27c9cd7e601632b3794e1c3344d37b86917ffb43 upstream. __remove_hrtimer() attempts to reprogram the clockevent device when the timer being removed is the next to expire. However, __remove_hrtimer() reprograms the clockevent *before* removing the timer from the timerqueue and thus when hrtimer_force_reprogram() finds the next timer to expire it finds the timer we're trying to remove. This is especially noticeable when the system switches to NOHz mode and the system tick is removed. The timer tick is removed from the system but the clockevent is programmed to wakeup in another HZ anyway. Silence the extra wakeup by removing the timer from the timerqueue before calling hrtimer_force_reprogram() so that we actually program the clockevent for the next timer to expire. This was broken by 998adc3 "hrtimers: Convert hrtimers to use timerlist infrastructure". Signed-off-by: Jeff Ohlstein <> Link: Signed-off-by: Thomas Gleixner <> Signed-off-by: Greg Kroah-Hartman <>
1 files changed, 4 insertions, 2 deletions
diff --git a/kernel/hrtimer.c b/kernel/hrtimer.c
index a9205e32a059..2043c08d36c8 100644
--- a/kernel/hrtimer.c
+++ b/kernel/hrtimer.c
@@ -885,10 +885,13 @@ static void __remove_hrtimer(struct hrtimer *timer,
struct hrtimer_clock_base *base,
unsigned long newstate, int reprogram)
+ struct timerqueue_node *next_timer;
if (!(timer->state & HRTIMER_STATE_ENQUEUED))
goto out;
- if (&timer->node == timerqueue_getnext(&base->active)) {
+ next_timer = timerqueue_getnext(&base->active);
+ timerqueue_del(&base->active, &timer->node);
+ if (&timer->node == next_timer) {
/* Reprogram the clock event device. if enabled */
if (reprogram && hrtimer_hres_active()) {
@@ -901,7 +904,6 @@ static void __remove_hrtimer(struct hrtimer *timer,
- timerqueue_del(&base->active, &timer->node);
if (!timerqueue_getnext(&base->active))
base->cpu_base->active_bases &= ~(1 << base->index);