get_next_timer_interrupt() returns a delta of (LONG_MAX > 1) in case there is no timer pending. On 64 bit machines this results in a multiplication overflow in tick_nohz_stop_sched_tick(). Reported by: Dave Miller <davem@davemloft.net> Make the return value a constant and limit the return value to a 32 bit value. When the max timeout value is returned, we can safely stop the tick timer device. The max jiffies delta results in a 12 days timeout for HZ=1000. In the long term the get_next_timer_interrupt() code needs to be reworked to return ktime instead of jiffies, but we have to wait until the last users of the original NO_IDLE_HZ code are converted.
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| @@ -666,7 +666,7 @@ static inline void __run_timers(tvec_base_t *base) · 665 unmodified lines | ||
| 666 | 666 | static unsigned long __next_timer_interrupt(tvec_base_t *base) |
| 667 | 667 | { |
| 668 | 668 | unsigned long timer_jiffies = base->timer_jiffies; |
| 669 | − unsigned long expires = timer_jiffies + (LONG_MAX >> 1); | |
| 669 | + unsigned long expires = timer_jiffies + NEXT_TIMER_MAX_DELTA; | |
| 670 | 670 | int index, slot, array, found = 0; |
| 671 | 671 | struct timer_list *nte; |
| 672 | 672 | tvec_t *varray[4]; |
| @@ -752,6 +752,14 @@ static unsigned long cmp_next_hrtimer_event(unsigned long now, · 79 unmodified lines | ||
| 752 | 752 | |
| 753 | 753 | tsdelta = ktime_to_timespec(hr_delta); |
| 754 | 754 | delta = timespec_to_jiffies(&tsdelta); |
| 755 | + | |
| 756 | + /* | |
| 757 | + * Limit the delta to the max value, which is checked in | |
| 758 | + * tick_nohz_stop_sched_tick(): | |
| 759 | + */ | |
| 760 | + if (delta > NEXT_TIMER_MAX_DELTA) | |
| 761 | + delta = NEXT_TIMER_MAX_DELTA; | |
| 762 | + | |
| 755 | 763 | /* |
| 756 | 764 | * Take rounding errors in to account and make sure, that it |
| 757 | 765 | * expires in the next tick. Otherwise we go into an endless |