Messages in this thread | | | From | Yang Yingliang <> | Subject | [PATCH 0/2] validate the delta of cycle_now and cycle_last on arm64 | Date | Tue, 27 Oct 2015 21:21:11 +0800 |
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In multi-core system, if the clock is not sync perfectly, it will make cycle_last that recorded by CPU-A is a little more than cycle_now that read by CPU-B. With the negative result, hrtimer_update_base() return a huge and wrong time. It leads to the cpu can not finish the while loop in hrtimer_interrupt() until the real nowtime which is returned from ktime_get() catch up with the wrong time on clock monotonic base.
Fix it by select config CLOCKSOURCE_VALIDATE_LAST_CYCLE.
Cc: Thomas Gleixner <tglx@linutronix.de>
Yang Yingliang (2): clocksource: replace cycle_last validation with an equal way arm64: validate the cycle_last to prevent time going backwards
arch/arm64/Kconfig | 1 + kernel/time/timekeeping_internal.h | 2 +- 2 files changed, 2 insertions(+), 1 deletion(-)
-- 2.5.0
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